{"video_id":"aXZ-NfMu60Q","title":"Are these a scam?","channel":"Linus Tech Tips","show":"Linus Tech Tips","published_at":"2026-03-05T14:53:29Z","duration_s":742,"segments":[{"start_s":0.0,"end_s":7.32,"text":"There are good privacy and security reasons that you might want a personal","speaker":null,"is_sponsor":0},{"start_s":4.6,"end_s":11.8,"text":"sized Faraday shield. New hacking tools are emerging every day and your ID, your","speaker":null,"is_sponsor":0},{"start_s":9.76,"end_s":17.48,"text":"car, and even your wallet could be at risk. But, in an industry that is a wash","speaker":null,"is_sponsor":0},{"start_s":15.2,"end_s":22.52,"text":"with pseudo-science and weapons grade blog damn, are any of these personal","speaker":null,"is_sponsor":0},{"start_s":20.2,"end_s":26.8,"text":"shields any good? That's the question that this user posed on the LTT [music]","speaker":null,"is_sponsor":0},{"start_s":24.72,"end_s":32.439,"text":"subreddit. And to answer them correctly, we're going to need a couple of things.","speaker":null,"is_sponsor":0},{"start_s":28.48,"end_s":36.52,"text":"First, a whole assortment of RF shields.","speaker":null,"is_sponsor":0},{"start_s":32.439,"end_s":39.04,"text":"Second, this RF meter. And third, a","speaker":null,"is_sponsor":0},{"start_s":36.52,"end_s":43.16,"text":"controlled environment so that we can ensure that any fluctuations in our","speaker":null,"is_sponsor":0},{"start_s":41.12,"end_s":48.04,"text":"measurements are due to the actual shield itself and not, say, someone in","speaker":null,"is_sponsor":0},{"start_s":45.92,"end_s":54.16,"text":"the lab over there downloading a file over the Wi-Fi. That is where our EMC","speaker":null,"is_sponsor":0},{"start_s":51.16,"end_s":56.44,"text":"chamber from Raymond EMC comes in. This","speaker":null,"is_sponsor":0},{"start_s":54.16,"end_s":61.76,"text":"bad boy gets us down to functionally zero RF, meaning that, yes, I'm going to","speaker":null,"is_sponsor":0},{"start_s":59.32,"end_s":66.84,"text":"test Faraday cages inside of an even bigger Faraday cage. We've got several","speaker":null,"is_sponsor":0},{"start_s":64.16,"end_s":72.6,"text":"popular cages from Amazon and one of our new writers, Danny, also MacGyvered one","speaker":null,"is_sponsor":0},{"start_s":69.36,"end_s":75.2,"text":"out of common household objects. Now,","speaker":null,"is_sponsor":0},{"start_s":72.6,"end_s":81.44,"text":"it's time for me to MacGyver this segway out of this cable and these twist ties","speaker":null,"is_sponsor":1},{"start_s":79.36,"end_s":85.04,"text":"to our sponsor, Squarespace. They're making it even easier than before to","speaker":null,"is_sponsor":1},{"start_s":83.36,"end_s":89.12,"text":"make a personalized website for your business. Their design AI tool is all","speaker":null,"is_sponsor":1},{"start_s":87.44,"end_s":92.16,"text":"you need to get started. Just answer a few quick questions and you're ready to","speaker":null,"is_sponsor":1},{"start_s":91.0,"end_s":96.52,"text":"go. Check out our link in the description to get started building your website today.","speaker":null,"is_sponsor":1},{"start_s":103.28,"end_s":109.04,"text":"A quick search online will yield a veritable buffet of Faraday shields,","speaker":null,"is_sponsor":0},{"start_s":107.0,"end_s":113.88,"text":"many of which appear to be quite similar looking and make similar claims. So,","speaker":null,"is_sponsor":0},{"start_s":111.56,"end_s":117.88,"text":"rather than ordering all of them, we chose a few different types to measure","speaker":null,"is_sponsor":0},{"start_s":116.2,"end_s":123.56,"text":"their effectiveness with a cell phone as a transmitter and our EMF strength meter","speaker":null,"is_sponsor":0},{"start_s":120.92,"end_s":128.16,"text":"as a receiver. Let's take a look at our candidates here. This bag here from","speaker":null,"is_sponsor":0},{"start_s":126.76,"end_s":133.56,"text":"Hadufi is pretty small and kind of flimsy","speaker":null,"is_sponsor":0},{"start_s":131.36,"end_s":139.08,"text":"feeling, but it's only 10 bucks. Meanwhile, Sam Folk makes this $25 box","speaker":null,"is_sponsor":0},{"start_s":137.04,"end_s":144.4,"text":"that comes with a free IQ test and also these","speaker":null,"is_sponsor":0},{"start_s":141.64,"end_s":147.8,"text":"pouches. One is the size for your keys and then the other is the size for your","speaker":null,"is_sponsor":0},{"start_s":146.04,"end_s":152.2,"text":"phone. So, I guess it's meant to live by the front door of a house where all of","speaker":null,"is_sponsor":0},{"start_s":149.92,"end_s":157.959,"text":"the calls come in via the landline. Anyway, the Mission Darkness bag is","speaker":null,"is_sponsor":0},{"start_s":155.36,"end_s":162.56,"text":"double the price of the Sam Folk, but also includes","speaker":null,"is_sponsor":0},{"start_s":159.72,"end_s":167.44,"text":"two layers of shielding cloth, so it must be twice as good then. Then,","speaker":null,"is_sponsor":0},{"start_s":164.84,"end_s":171.4,"text":"finally, we've got this RFID blocking wallet from our partners over at Ridge.","speaker":null,"is_sponsor":0},{"start_s":169.84,"end_s":175.52,"text":"We'll have links to all of the stuff down below. Finally, finally, we picked","speaker":null,"is_sponsor":0},{"start_s":173.8,"end_s":180.72,"text":"up some bulk shielding fabric from Amradield Amradield Amradield I'm","speaker":null,"is_sponsor":0},{"start_s":178.959,"end_s":184.08,"text":"rattled by my inability to pronounce this [music] word. The point is this","speaker":null,"is_sponsor":0},{"start_s":182.2,"end_s":188.68,"text":"will let you make an RFID blocking whatever you want and we will make one","speaker":null,"is_sponsor":0},{"start_s":186.64,"end_s":192.76,"text":"of those. But, before we do that, we're going to do a basic test on the fabric","speaker":null,"is_sponsor":0},{"start_s":190.4,"end_s":195.72,"text":"by itself. While we do have a handful of different tools for measuring electric","speaker":null,"is_sponsor":0},{"start_s":194.36,"end_s":200.32,"text":"fields, we're going to keep things really simple today with our Extech EMF","speaker":null,"is_sponsor":0},{"start_s":198.239,"end_s":205.84,"text":"meter. You can see that here inside the chamber with the door closed, we're","speaker":null,"is_sponsor":0},{"start_s":202.36,"end_s":208.32,"text":"sitting at virtually zero. Just","speaker":null,"is_sponsor":0},{"start_s":205.84,"end_s":213.76,"text":"1917 [music] mV per meter. That is orders of","speaker":null,"is_sponsor":0},{"start_s":211.16,"end_s":217.8,"text":"magnitude less than just outside these walls. [music] Now, all we got to do is","speaker":null,"is_sponsor":0},{"start_s":215.2,"end_s":221.88,"text":"position this about 40 cm from our test platform and grab a phone to put on the","speaker":null,"is_sponsor":0},{"start_s":220.56,"end_s":226.92,"text":"pedestal. We left all our phones outside. Oops. One moment, please.","speaker":null,"is_sponsor":0},{"start_s":228.239,"end_s":233.68,"text":"First up is the Hadufi bag. Let's start","speaker":null,"is_sponsor":0},{"start_s":232.08,"end_s":237.84,"text":"by getting a baseline though. Immediately upon bringing a phone in","speaker":null,"is_sponsor":0},{"start_s":235.64,"end_s":242.16,"text":"here, you can see it's just searching for network, sending [music] out pings","speaker":null,"is_sponsor":0},{"start_s":240.0,"end_s":249.8,"text":"for other Bluetooth devices, Wi-Fi devices. We're sitting at anywhere from","speaker":null,"is_sponsor":0},{"start_s":244.36,"end_s":251.84,"text":"around 1 to 2 and 1/2 volts per meter. A","speaker":null,"is_sponsor":0},{"start_s":249.8,"end_s":257.959,"text":"lot more. However, now that it's kind of gone to sleep, it looks like we're","speaker":null,"is_sponsor":0},{"start_s":253.64,"end_s":260.16,"text":"closer to around 700 millivolts to 1.2","speaker":null,"is_sponsor":0},{"start_s":257.959,"end_s":267.16,"text":"up and it spiked up to two again. What is your logic? Pro logic?","speaker":null,"is_sponsor":0},{"start_s":263.56,"end_s":269.4,"text":"Realistically, anywhere from around 650","speaker":null,"is_sponsor":0},{"start_s":267.16,"end_s":274.04,"text":"millivolts to [music] 2 and 1/2 volts per meter. Pretty broad,","speaker":null,"is_sponsor":0},{"start_s":271.72,"end_s":277.32,"text":"but compared to what we saw when the room didn't have an iPhone in it, I","speaker":null,"is_sponsor":0},{"start_s":275.68,"end_s":282.6,"text":"think we should be able to tell if this is doing anything. First up is the ha","speaker":null,"is_sponsor":0},{"start_s":279.96,"end_s":282.6,"text":"dufy.","speaker":null,"is_sponsor":0},{"start_s":283.6,"end_s":290.6,"text":"They were very specific about folding it twice and that actually makes a ton of","speaker":null,"is_sponsor":0},{"start_s":288.36,"end_s":294.6,"text":"sense because just one fold could leave gaps where the dangerous RF could leak","speaker":null,"is_sponsor":0},{"start_s":293.36,"end_s":298.0,"text":"out. I'm going to aim [music] to put it in the same spot on the pedestal here","speaker":null,"is_sponsor":0},{"start_s":296.64,"end_s":303.16,"text":"and let's see what our measurements look like.","speaker":null,"is_sponsor":0},{"start_s":300.08,"end_s":306.64,"text":"Oh, wow. I don't know exactly what I was","speaker":null,"is_sponsor":0},{"start_s":303.16,"end_s":310.16,"text":"expecting, but that wasn't it.","speaker":null,"is_sponsor":0},{"start_s":306.64,"end_s":310.16,"text":"High five ha dufy.","speaker":null,"is_sponsor":0},{"start_s":310.8,"end_s":317.32,"text":"Left me hanging, but it didn't leave me hanging in terms of performance. This is","speaker":null,"is_sponsor":0},{"start_s":314.84,"end_s":321.56,"text":"functionally identical to what we had before we brought the iPhone in here.","speaker":null,"is_sponsor":0},{"start_s":319.36,"end_s":328.84,"text":"Next up Wait, hold on. Before we move on, the ha dufy also claims that it can","speaker":null,"is_sponsor":0},{"start_s":324.52,"end_s":329.88,"text":"withstand temperatures of up to 1,000°","speaker":null,"is_sponsor":0},{"start_s":328.84,"end_s":336.88,"text":"F. I assume you like your phone not broken though, so what kind of a claim is that?","speaker":null,"is_sponsor":0},{"start_s":334.64,"end_s":342.2,"text":"What is this bag for? You never know if in the apocalypse you might need to very","speaker":null,"is_sponsor":0},{"start_s":338.96,"end_s":345.84,"text":"specifically withstand 1,000° F. Next","speaker":null,"is_sponsor":0},{"start_s":342.2,"end_s":347.96,"text":"up, we've got our Sam folk box. Oh,","speaker":null,"is_sponsor":0},{"start_s":345.84,"end_s":352.92,"text":"leaking a little. And good. You really got to close it","speaker":null,"is_sponsor":0},{"start_s":350.6,"end_s":352.92,"text":"though.","speaker":null,"is_sponsor":0},{"start_s":360.16,"end_s":367.0,"text":"And we found the same thing in our next couple of tests, meaning that everything","speaker":null,"is_sponsor":0},{"start_s":363.84,"end_s":369.04,"text":"from the boxes to the bags to the loose","speaker":null,"is_sponsor":0},{"start_s":367.0,"end_s":373.28,"text":"fabric performed pretty much identically.","speaker":null,"is_sponsor":0},{"start_s":370.64,"end_s":377.0,"text":"The question now is why though? For wallets and key fobs, the answer is","speaker":null,"is_sponsor":0},{"start_s":375.12,"end_s":381.0,"text":"pretty [music] obvious to keep your cards from being skimmed and to keep","speaker":null,"is_sponsor":0},{"start_s":378.48,"end_s":385.64,"text":"your car from being stolen. But so many of these companies market these products","speaker":null,"is_sponsor":0},{"start_s":383.32,"end_s":390.52,"text":"for cell phone use. They do understand how cell phones work,","speaker":null,"is_sponsor":0},{"start_s":387.919,"end_s":395.2,"text":"right? Here's a Linus Tech Tip, free of charge. If you're ever tempted to put","speaker":null,"is_sponsor":0},{"start_s":392.8,"end_s":399.76,"text":"your phone into one of these shields for any extended period of time, just put it","speaker":null,"is_sponsor":0},{"start_s":397.24,"end_s":404.4,"text":"in airplane mode instead. It offers up the same security benefits, that is to","speaker":null,"is_sponsor":0},{"start_s":402.04,"end_s":407.96,"text":"say little to none, but it comes with none of the downsides of putting your","speaker":null,"is_sponsor":0},{"start_s":406.0,"end_s":413.28,"text":"phone inside a Faraday cage. Like people, your phone gets lonely without a","speaker":null,"is_sponsor":0},{"start_s":410.4,"end_s":417.16,"text":"connection and it will just keep swiping desperately for a wireless hookup until","speaker":null,"is_sponsor":0},{"start_s":415.96,"end_s":421.36,"text":"finally its social battery is drained and it","speaker":null,"is_sponsor":0},{"start_s":419.36,"end_s":425.68,"text":"doesn't want to do anything anymore. The Ridge Wallet claims to offer defense","speaker":null,"is_sponsor":0},{"start_s":423.4,"end_s":430.12,"text":"against RFID card skimmers, but this raises some questions. How can it do so","speaker":null,"is_sponsor":0},{"start_s":428.32,"end_s":434.0,"text":"if it doesn't even form a complete enclosure around your cards? To find","speaker":null,"is_sponsor":0},{"start_s":432.36,"end_s":439.24,"text":"out, we're going to need a different test methodology. Because those RFID","speaker":null,"is_sponsor":0},{"start_s":436.8,"end_s":444.6,"text":"chips are passive, [music] being powered on by the reader through induction","speaker":null,"is_sponsor":0},{"start_s":441.88,"end_s":448.64,"text":"before they actually transmit any data, we can't just","speaker":null,"is_sponsor":0},{"start_s":446.24,"end_s":453.68,"text":"poke an EMF meter at it. We're going to have to power up the card first. That","speaker":null,"is_sponsor":0},{"start_s":451.6,"end_s":457.0,"text":"is where the Flipper Zero comes in. In theory, it's as simple as putting the","speaker":null,"is_sponsor":0},{"start_s":455.24,"end_s":460.919,"text":"Flipper against the back of the card and it'll power up that chip and grab a","speaker":null,"is_sponsor":0},{"start_s":458.919,"end_s":465.96,"text":"reading. Just like that. Now, the Flipper is scrambled because it","speaker":null,"is_sponsor":0},{"start_s":463.64,"end_s":473.0,"text":"doesn't actually try to be a device for theft. But, this is enough to find out","speaker":null,"is_sponsor":0},{"start_s":468.52,"end_s":473.0,"text":"if the Ridge Wallet will block us.","speaker":null,"is_sponsor":0},{"start_s":473.6,"end_s":479.36,"text":"It works, which is nice because as a long-time partner, it would have been","speaker":null,"is_sponsor":0},{"start_s":477.76,"end_s":484.0,"text":"awkward if we had to be the ones to expose that the Ridge Wallet doesn't","speaker":null,"is_sponsor":0},{"start_s":481.48,"end_s":489.48,"text":"work cuz it doesn't enclose the card. Uh presumably that doesn't matter thanks to","speaker":null,"is_sponsor":0},{"start_s":486.04,"end_s":492.44,"text":"the extremely low range and low power","speaker":null,"is_sponsor":0},{"start_s":489.48,"end_s":497.04,"text":"operation of RFID. Now that we validated it, that totally makes sense. I just","speaker":null,"is_sponsor":0},{"start_s":495.0,"end_s":501.2,"text":"hadn't really thought about it before. So, now my only remaining question is","speaker":null,"is_sponsor":0},{"start_s":499.64,"end_s":505.96,"text":"do I need any of these off-the-shelf solutions or could I just as easily put","speaker":null,"is_sponsor":0},{"start_s":503.76,"end_s":511.84,"text":"something together myself? YouTube is chock-full of DIY RF blocking solutions","speaker":null,"is_sponsor":0},{"start_s":509.48,"end_s":515.719,"text":"with the most common being the old CIA classic, the wrap it before they wiretap","speaker":null,"is_sponsor":0},{"start_s":514.719,"end_s":522.159,"text":"it with aluminum foil, of course. It's um","speaker":null,"is_sponsor":0},{"start_s":519.44,"end_s":525.971,"text":"not exactly a durable material, though, is it? That's where this solution comes","speaker":null,"is_sponsor":0},{"start_s":525.44,"end_s":530.96,"text":"in. >> [music] >> This is a cheap resealable Ziploc bag","speaker":null,"is_sponsor":0},{"start_s":529.16,"end_s":536.72,"text":"with some metal foil tape in an overlapping pattern. Theoretically, by","speaker":null,"is_sponsor":0},{"start_s":533.92,"end_s":542.0,"text":"following the same installation process that we did with our other bags, that is","speaker":null,"is_sponsor":0},{"start_s":538.76,"end_s":543.6,"text":"to say, folding it over and over and","speaker":null,"is_sponsor":0},{"start_s":542.0,"end_s":548.68,"text":"then putting a little clamp on it, we should","speaker":null,"is_sponsor":0},{"start_s":545.64,"end_s":550.44,"text":"be able to block any signals in or out.","speaker":null,"is_sponsor":0},{"start_s":548.68,"end_s":554.72,"text":"While we're at it, I also want to try this cookie tin and how does this hat","speaker":null,"is_sponsor":0},{"start_s":552.8,"end_s":559.72,"text":"figure into it? Are you just Are you just trying to protect me or what's the","speaker":null,"is_sponsor":0},{"start_s":556.48,"end_s":560.76,"text":"idea here? Of course. Thanks, Danny.","speaker":null,"is_sponsor":0},{"start_s":559.72,"end_s":566.24,"text":"This one's not available at lttstore.com, but we do have hats. You","speaker":null,"is_sponsor":1},{"start_s":562.839,"end_s":566.24,"text":"can check them out at the link below.","speaker":null,"is_sponsor":1},{"start_s":568.839,"end_s":578.24,"text":"And as we've confirmed before on this channel, tinfoil works, but","speaker":null,"is_sponsor":0},{"start_s":574.52,"end_s":578.24,"text":"it's not exactly convenient.","speaker":null,"is_sponsor":0},{"start_s":578.28,"end_s":582.0,"text":"Why don't we try our reusable bag?","speaker":null,"is_sponsor":0},{"start_s":585.56,"end_s":592.24,"text":"And like the tin foil, it works. Now, let's try something that","speaker":null,"is_sponsor":0},{"start_s":590.6,"end_s":595.88,"text":"you might already have in your house sitting in your garbage or recycling","speaker":null,"is_sponsor":0},{"start_s":593.84,"end_s":599.88,"text":"bin. This metal cookie tin should make a perfect shield now that it's empty.","speaker":null,"is_sponsor":0},{"start_s":600.641,"end_s":608.84,"text":">> [laughter] >> Anyhow, let's go ahead and put that in there.","speaker":null,"is_sponsor":0},{"start_s":605.16,"end_s":610.6,"text":"And voila, perfect. You might think, but","speaker":null,"is_sponsor":0},{"start_s":608.84,"end_s":613.88,"text":"we actually found that the orientation mattered a little bit and the seam,","speaker":null,"is_sponsor":0},{"start_s":612.96,"end_s":618.72,"text":"well, the seam did have some leakage, but apparently now it doesn't. Since we're","speaker":null,"is_sponsor":0},{"start_s":616.84,"end_s":623.16,"text":"at it, one final thing we wanted to test was these ESD safe bags that many","speaker":null,"is_sponsor":0},{"start_s":621.08,"end_s":627.92,"text":"electronics ship in. There are rumors on Reddit that, depending on the type, it","speaker":null,"is_sponsor":0},{"start_s":625.36,"end_s":634.08,"text":"can block signals for devices inside them.","speaker":null,"is_sponsor":0},{"start_s":629.28,"end_s":634.08,"text":"I don't actually expect this to work.","speaker":null,"is_sponsor":0},{"start_s":635.88,"end_s":642.56,"text":"Huh. [laughter] Totally works. It's maybe not quite as","speaker":null,"is_sponsor":0},{"start_s":640.36,"end_s":646.64,"text":"low as some of the stuff we've seen, but it's pretty much there.","speaker":null,"is_sponsor":0},{"start_s":644.4,"end_s":650.36,"text":"With that said, I fully expected this kind to do nothing.","speaker":null,"is_sponsor":0},{"start_s":652.88,"end_s":660.56,"text":"Yeah. That's [music] pretty rough. It might do something, but not much. All of","speaker":null,"is_sponsor":0},{"start_s":658.08,"end_s":666.44,"text":"which leaves only one thing to test, the bulk fabric. Now, I'm not saying that 5G","speaker":null,"is_sponsor":0},{"start_s":663.96,"end_s":671.16,"text":"signals are dangerous for your junk. I'm just saying that um","speaker":null,"is_sponsor":0},{"start_s":669.2,"end_s":675.68,"text":"if you believed that, this underwear might do something.","speaker":null,"is_sponsor":0},{"start_s":674.28,"end_s":680.8,"text":"You want to check it? There's nothing there. Oh, come now.","speaker":null,"is_sponsor":0},{"start_s":678.44,"end_s":684.96,"text":"There's at least a segway to our sponsor, Squarespace. It's the","speaker":null,"is_sponsor":1},{"start_s":682.68,"end_s":689.12,"text":"one-stop shop for all things you and your business need to build a fully","speaker":null,"is_sponsor":1},{"start_s":686.92,"end_s":693.2,"text":"personalized website. They have a ton of templates for you to get started or you","speaker":null,"is_sponsor":1},{"start_s":691.36,"end_s":697.08,"text":"can even use their design intelligence tool to make something that aligns with","speaker":null,"is_sponsor":1},{"start_s":694.84,"end_s":701.52,"text":"specifically your brand. There's millions of URLs still unclaimed out","speaker":null,"is_sponsor":1},{"start_s":699.56,"end_s":705.6,"text":"there, and Squarespace will help you lock in yours with all of the necessary","speaker":null,"is_sponsor":1},{"start_s":703.52,"end_s":708.52,"text":"privacy and security features included. And if you want to do business straight","speaker":null,"is_sponsor":1},{"start_s":707.04,"end_s":712.76,"text":"from the website, they can help you process all kinds of payments from","speaker":null,"is_sponsor":1},{"start_s":710.56,"end_s":716.28,"text":"direct debit to Apple Pay to Klarna and many more. And it's all there for you.","speaker":null,"is_sponsor":1},{"start_s":714.96,"end_s":720.04,"text":"See why millions of people trust Squarespace for their websites. Start","speaker":null,"is_sponsor":1},{"start_s":718.08,"end_s":723.96,"text":"building your website today and receive 10% off your first purchase by visiting","speaker":null,"is_sponsor":1},{"start_s":721.76,"end_s":727.64,"text":"squarespace.com/LTT. If you guys enjoyed this video and you","speaker":null,"is_sponsor":1},{"start_s":725.2,"end_s":732.04,"text":"want to learn more about RF and how this EMC chamber works, check out the","speaker":null,"is_sponsor":1},{"start_s":729.4,"end_s":735.68,"text":"unboxing we did. It was very generous of Raymond EMC to provide this chamber so","speaker":null,"is_sponsor":1},{"start_s":733.92,"end_s":739.96,"text":"that we could bring you guys important tech tips like","speaker":null,"is_sponsor":0},{"start_s":738.0,"end_s":743.16,"text":"whether this fabric protects your junk from the 5G.","speaker":null,"is_sponsor":0}],"full_text":"There are good privacy and security reasons that you might want a personal sized Faraday shield. New hacking tools are emerging every day and your ID, your car, and even your wallet could be at risk. But, in an industry that is a wash with pseudo-science and weapons grade blog damn, are any of these personal shields any good? That's the question that this user posed on the LTT [music] subreddit. And to answer them correctly, we're going to need a couple of things. First, a whole assortment of RF shields. Second, this RF meter. And third, a controlled environment so that we can ensure that any fluctuations in our measurements are due to the actual shield itself and not, say, someone in the lab over there downloading a file over the Wi-Fi. That is where our EMC chamber from Raymond EMC comes in. This bad boy gets us down to functionally zero RF, meaning that, yes, I'm going to test Faraday cages inside of an even bigger Faraday cage. We've got several popular cages from Amazon and one of our new writers, Danny, also MacGyvered one out of common household objects. Now, it's time for me to MacGyver this segway out of this cable and these twist ties to our sponsor, Squarespace. They're making it even easier than before to make a personalized website for your business. Their design AI tool is all you need to get started. Just answer a few quick questions and you're ready to go. Check out our link in the description to get started building your website today. A quick search online will yield a veritable buffet of Faraday shields, many of which appear to be quite similar looking and make similar claims. So, rather than ordering all of them, we chose a few different types to measure their effectiveness with a cell phone as a transmitter and our EMF strength meter as a receiver. Let's take a look at our candidates here. This bag here from Hadufi is pretty small and kind of flimsy feeling, but it's only 10 bucks. Meanwhile, Sam Folk makes this $25 box that comes with a free IQ test and also these pouches. One is the size for your keys and then the other is the size for your phone. So, I guess it's meant to live by the front door of a house where all of the calls come in via the landline. Anyway, the Mission Darkness bag is double the price of the Sam Folk, but also includes two layers of shielding cloth, so it must be twice as good then. Then, finally, we've got this RFID blocking wallet from our partners over at Ridge. We'll have links to all of the stuff down below. Finally, finally, we picked up some bulk shielding fabric from Amradield Amradield Amradield I'm rattled by my inability to pronounce this [music] word. The point is this will let you make an RFID blocking whatever you want and we will make one of those. But, before we do that, we're going to do a basic test on the fabric by itself. While we do have a handful of different tools for measuring electric fields, we're going to keep things really simple today with our Extech EMF meter. You can see that here inside the chamber with the door closed, we're sitting at virtually zero. Just 1917 [music] mV per meter. That is orders of magnitude less than just outside these walls. [music] Now, all we got to do is position this about 40 cm from our test platform and grab a phone to put on the pedestal. We left all our phones outside. Oops. One moment, please. First up is the Hadufi bag. Let's start by getting a baseline though. Immediately upon bringing a phone in here, you can see it's just searching for network, sending [music] out pings for other Bluetooth devices, Wi-Fi devices. We're sitting at anywhere from around 1 to 2 and 1/2 volts per meter. A lot more. However, now that it's kind of gone to sleep, it looks like we're closer to around 700 millivolts to 1.2 up and it spiked up to two again. What is your logic? Pro logic? Realistically, anywhere from around 650 millivolts to [music] 2 and 1/2 volts per meter. Pretty broad, but compared to what we saw when the room didn't have an iPhone in it, I think we should be able to tell if this is doing anything. First up is the ha dufy. They were very specific about folding it twice and that actually makes a ton of sense because just one fold could leave gaps where the dangerous RF could leak out. I'm going to aim [music] to put it in the same spot on the pedestal here and let's see what our measurements look like. Oh, wow. I don't know exactly what I was expecting, but that wasn't it. High five ha dufy. Left me hanging, but it didn't leave me hanging in terms of performance. This is functionally identical to what we had before we brought the iPhone in here. Next up Wait, hold on. Before we move on, the ha dufy also claims that it can withstand temperatures of up to 1,000° F. I assume you like your phone not broken though, so what kind of a claim is that? What is this bag for? You never know if in the apocalypse you might need to very specifically withstand 1,000° F. Next up, we've got our Sam folk box. Oh, leaking a little. And good. You really got to close it though. And we found the same thing in our next couple of tests, meaning that everything from the boxes to the bags to the loose fabric performed pretty much identically. The question now is why though? For wallets and key fobs, the answer is pretty [music] obvious to keep your cards from being skimmed and to keep your car from being stolen. But so many of these companies market these products for cell phone use. They do understand how cell phones work, right? Here's a Linus Tech Tip, free of charge. If you're ever tempted to put your phone into one of these shields for any extended period of time, just put it in airplane mode instead. It offers up the same security benefits, that is to say little to none, but it comes with none of the downsides of putting your phone inside a Faraday cage. Like people, your phone gets lonely without a connection and it will just keep swiping desperately for a wireless hookup until finally its social battery is drained and it doesn't want to do anything anymore. The Ridge Wallet claims to offer defense against RFID card skimmers, but this raises some questions. How can it do so if it doesn't even form a complete enclosure around your cards? To find out, we're going to need a different test methodology. Because those RFID chips are passive, [music] being powered on by the reader through induction before they actually transmit any data, we can't just poke an EMF meter at it. We're going to have to power up the card first. That is where the Flipper Zero comes in. In theory, it's as simple as putting the Flipper against the back of the card and it'll power up that chip and grab a reading. Just like that. Now, the Flipper is scrambled because it doesn't actually try to be a device for theft. But, this is enough to find out if the Ridge Wallet will block us. It works, which is nice because as a long-time partner, it would have been awkward if we had to be the ones to expose that the Ridge Wallet doesn't work cuz it doesn't enclose the card. Uh presumably that doesn't matter thanks to the extremely low range and low power operation of RFID. Now that we validated it, that totally makes sense. I just hadn't really thought about it before. So, now my only remaining question is do I need any of these off-the-shelf solutions or could I just as easily put something together myself? YouTube is chock-full of DIY RF blocking solutions with the most common being the old CIA classic, the wrap it before they wiretap it with aluminum foil, of course. It's um not exactly a durable material, though, is it? That's where this solution comes in. >> [music] >> This is a cheap resealable Ziploc bag with some metal foil tape in an overlapping pattern. Theoretically, by following the same installation process that we did with our other bags, that is to say, folding it over and over and then putting a little clamp on it, we should be able to block any signals in or out. While we're at it, I also want to try this cookie tin and how does this hat figure into it? Are you just Are you just trying to protect me or what's the idea here? Of course. Thanks, Danny. This one's not available at lttstore.com, but we do have hats. You can check them out at the link below. And as we've confirmed before on this channel, tinfoil works, but it's not exactly convenient. Why don't we try our reusable bag? And like the tin foil, it works. Now, let's try something that you might already have in your house sitting in your garbage or recycling bin. This metal cookie tin should make a perfect shield now that it's empty. >> [laughter] >> Anyhow, let's go ahead and put that in there. And voila, perfect. You might think, but we actually found that the orientation mattered a little bit and the seam, well, the seam did have some leakage, but apparently now it doesn't. Since we're at it, one final thing we wanted to test was these ESD safe bags that many electronics ship in. There are rumors on Reddit that, depending on the type, it can block signals for devices inside them. I don't actually expect this to work. Huh. [laughter] Totally works. It's maybe not quite as low as some of the stuff we've seen, but it's pretty much there. With that said, I fully expected this kind to do nothing. Yeah. That's [music] pretty rough. It might do something, but not much. All of which leaves only one thing to test, the bulk fabric. Now, I'm not saying that 5G signals are dangerous for your junk. I'm just saying that um if you believed that, this underwear might do something. You want to check it? There's nothing there. Oh, come now. There's at least a segway to our sponsor, Squarespace. It's the one-stop shop for all things you and your business need to build a fully personalized website. They have a ton of templates for you to get started or you can even use their design intelligence tool to make something that aligns with specifically your brand. There's millions of URLs still unclaimed out there, and Squarespace will help you lock in yours with all of the necessary privacy and security features included. And if you want to do business straight from the website, they can help you process all kinds of payments from direct debit to Apple Pay to Klarna and many more. And it's all there for you. See why millions of people trust Squarespace for their websites. Start building your website today and receive 10% off your first purchase by visiting squarespace.com/LTT. If you guys enjoyed this video and you want to learn more about RF and how this EMC chamber works, check out the unboxing we did. It was very generous of Raymond EMC to provide this chamber so that we could bring you guys important tech tips like whether this fabric protects your junk from the 5G."}