This exists

You can buy it as a Christmas gift! It’s only $70!

There are other versions. There are a whole lot of these things!

In case you’re wondering what it is, it’s a small Faraday cage for people who are sensitive (they think) to EMF radiation. These are designed for you to place your WiFi router in so that it will stop hosing your house with 2.4-5 gigaherz radiation. Which is the whole point of a WiFi router. So yeah, you go drop $100 on a router so you can browse the internet, and then cage it up in a metal box so you can’t browse the internet. Brilliant!

Another amazing thing: those cages have a significant number of 5-star reviews. I guess they work!


  1. zippythepinhead says

    Because you can’t spell “radiation” without the letters “I”, “D”, “I”, “O”, “T”.

  2. Pierce R. Butler says

    It’s only $70!

    With that, you can buy enough Ethernet cable to connect to your switch in all but the largest of houses.

  3. zippythepinhead says

    For true peace of mind, you need a daily recto-magneto-gram ™(R), now with indisposable probes!

  4. says

    OTOH, a smaller one might not be a bad place to keep your wallet and passport, especially when travelling… if only because the shiny will make them easier to find while their RFI chips can’t be interrogated by miscreants.

    And it will irritate TSA, which is almost always worthwhile.

    Hey, I know: Put your TV remote in it!

  5. PaulBC says

    I seriously thought about buying a metal box for my car keys when I got a new car a few years ago. I had a habit of trying the drivers side door after getting out to make sure it was really locked, and of course this fails if it opens when your key is in proximity. I eventually decided it was an obsessive habit anyway. Sometimes I still check the other doors.

    Other than that, I can’t think of what I would need a Faraday cage for.

    When I saw the picture, I just assumed it was for holding your spiders during transport. It might work if you could get them to go in, but there are probably better ways.

  6. wzrd1 says

    Blah, used to run shielded eternity cables through grounded steel conduit, all joints epoxies or welded.
    Laughably, we used to test pagers inside of a microwave oven sized Faraday shield, using a precision signal source. It was a final QA proving stage.

    We used to be required to place our hell phones into a locking Faraday shield before entry into the SCIF. Predictably, the battery would be depleted when we departed, those depleted in airplane mode were examined…

  7. slithey tove (twas brillig (stevem)) says

    Use of this product should not at all affect signal range and internet speed.

    I don’t understand. —oh I see . it doesn’t block internet speed, nor the signal range. It blocks the signal strength it’s on the customer to use a device that can deal with nanowatt signals instead of the conventional milliwatts. Amazing how easy it is to prey on lack of understanding how WiFi connects from router to PC, and the fantasy of EMF allergies.
    I am a EE with Masters Degree and well versed in wireless signals.

  8. christoph says

    @ PaulBC, # 10: The annoying thing about those kinds of car keys is that the door will unlock for anyone who touches it if you (and the key) are close to the car.

  9. says

    If we’re going to be pedantic about vote margins, Joe Biden’s (7.0 million) is about the same as Warren Harding’s in 1920 or FDR’s in 1932. Richard Nixon’s 1972 vote margin (17.9 million) is largest, followed by Ronald Reagan’s 1984 (16.8 million), Lyndon Johnson’s 1964 (15.9 million), and FDR’s 1936 (11.0 million) vote margins.

  10. says

    Sorry about that. This was a comment on a different thread; I don’t know how I managed to post it here as well. Feel free to delete it.

  11. whheydt says

    I really prefer to use wired connections, anyway. I’m slowly migrating from CAT-5/5A to CAT-6/6E and have upgraded my own switches to 1Gb/s. (And…someday…those will have to be replaced with 2.4Gb/s, but nothing in the house handles that…yet. The switch side of the ISP supplied router/modem is only 100Mb/s, so the faster gear only applies to transfers on the LAN.) There are others in the household that routinely use WiFi.

    What also exists, is readily available, and one can see uses for, are RF shielded slip covers for chipped cards, like ATM or credit cards, to prevent them from being read when you don’t want them to. I’ve also seen references to shielded wallets for the same purpose.

    Locally, there are car pool/paid priority freeway lanes. If you have a toll transponder, but you have enough people in the car for the carpool rules to apply, you want to put the transponder in something shielded so you don’t get charged for using the lane when it should be free for you. Carrying a big enough piece of aluminum foil to wrap it in works just fine and is vastly cheaper than any purpose-built commercial product.

  12. unclefrogy says

    I prefer a wired connection and do not mind funky wiring paths around the house (not hidden in walls or under the floor..)
    I have entertained the thought of just such a device but never went through the trouble to make one. looks very well made and at a fare price. I live in a very urban environment and realize there is already so much low level EMF and RFI around that protecting myself would be difficult.
    I will add that this old house was covered in asbestos shingle siding long before I bought it it is stable so no problem with it except they installed an aluminum foil backed vapor barrier which has caused some difficulty with RF reception at least that is what I think is the source of the difficulty. Now if I installed grounded copper window screens and metal roof I would be set.
    uncle frogy

  13. seachange says

    It might be sensible to buy this but not for the reason listed, and not at the cost.

    My router is WiFi even though I do not want it to be, it has Ethernet ports in back. An equivalent modem-router which is not WiFI is much more expensive. All my connections are cabled with Ethernet 2. While I have set all of my devices to not use WiFi a lot of them will obnoxiously default to this when reset even though my wired connections along the ceiling are faster and more reliable.

    I don’t want to broadcast my data, this is an opportunity to hack. I don’t want my devices working slowly, and a box like this would instantly alert me to restart fails.

  14. KG says

    I’ve thought of buying a Faraday cage to keep my backup hard drive in, in case of an EMF pulse from a high altitude nuke or a Carrington event. Anyone know if it would actually protect the drive in such a case?

  15. chris says

    That looks like a wire mesh box that holds letter size paper that I used to see in a Storables store (now closed).

    I told my electrical engineer spouse about this while he was making lunch. First he tilted his head, looked a but confused, and then just broke out in laughter. He wondered if this was a plan to prevent folks from getting teh internets.

  16. doumakes says

    Unlike various other examples of woo, this one at least makes a claim that’s testable. Put your cell phone in the box. Have a family member call you. If it rings, the manufacture is full of shit.

    I used to have a “Faraday cage” passport pouch, but it failed the test. I’m in the market for one that works.

  17. michaelcrichton says

    unclefrogy, seachange: it was no doubt originally designed for users like you, who had a genuine need for it. But then they realized they could make more money marketing it to nitwits who wanted to protect their routers from getting the 5g Covid. :-)

  18. indianajones says

    @20 Yeah, a ruined hard drive would be the absolute last straw for me on a day with nuclear weapons in it.

    Ahem. Anyway, probably not. A Faraday cage won’t knock out all RF signal, just a lot of it. Think of it this way: Trees don’t conduct electricity. But if you put 7 million or so volts over it, there’s your lightning strike and accompanying wrecked tree.

  19. Nerd of Redhead, Dances OM Trolls says

    These remind me of the SS cages the quality control department used in the automatic washer (think lab equipment dishwasher) for items like weighing boats, forceps, stir bars, and other non-disposable equipment. The automatic washer was used for quality assurance reasons.

  20. bcw bcw says

    @20. To get a big EMF pulse on a device it needs something acting as an antenna. A sky pulse mostly destroys things by being picked up by the miles of power lines to your house which then blows up devices that are plugged in (use surge protectors.) A car is big enough that it has pretty good pickup but can act as a Faraday cage itself. A disk drive not plugged into anything should be OK – the data itself, totally, but the electronics in the drive could get damaged if there is a big enough voltage spike, but this is unlikely.

  21. bcw bcw says

    The reviews are scary “I’m really sensitive to EMF and my Mac-mini makes my head hurt even if I use a really long cable so the display is in the next room.”
    I can understand, in my case loud colors make my ears hurt. jez kidding.

    I would love to unlove to unplug that Mac on this guy without telling him.

  22. R. L. Foster says

    Or you could just move to the United States National Radio Quiet Zone if you think EMF radiation makes you ill. Only problem with that is that it’s mostly in West Virginia.

  23. PaulBC says

    No matter what kind of Faraday cage I buy, my Maxwell’s Demon keeps figuring out how to escape.

  24. christoph says

    @KG, # 20: Your drive might be okay, but you’d need to be wearing about 2,000,000 SPF sunblock.

  25. says

    @#20, KG:

    The pulse might or might not harm the drive directly. What’s far more likely is a massive power surge coming in through the power lines, overwhelming your surge protector and the guts of your computer and hitting the drive by the ground in the cable. (All the major connection schemes have a ground pin or use the plug itself.)

    If you want to be paranoid about this kind of scenario, get a cheap SDXC drive (if you don’t have one built in) and make regular backups to cheap SDXC cards, using two in alternation. They’re fast, small, basically immune to radiation, and increasingly cheap.

  26. John Morales says

    @20, put it into a DVD, or some other form of optical storage.

    (Why ameliorate when you can avoid?)

  27. leerudolph says

    DAMNIT. Sorry for the premature “Post Comment”.

    I was just going to add “and then weld it shut.”

  28. microraptor says

    I wonder how many of the five star votes on the home Faraday cage are from trolls trying to get stupid people into actually buying one?

  29. says

    @#32, John Morales:

    Meh. DVDs are awkward to use, relatively low-capacity, and the media often isn’t rated to be used with drives fast enough to beat SD cards. (A Class 10/UC 1 SD card, which is the typical speed now, guarantees a minimum of 10 MB/sec sequential write speed; DVDs have to be at least 7.22x speed to match that and a lot of the media is only officially rated for 2x or 4x.) And the price/capacity ratio isn’t really all that good — Walmart will sell you a spindle of 100 DVD-R or DVD+R media (of who knows what quality) for $24, which is theoretically 470 GB, but they’ll sell you two 256 GB micro SD cards for $22 — and the SD cards will be reusable, while you have to pay a lot more for DVD-RW. Then, in addition, the DVD drive will have moving parts, and will therefore be fragile, while the SD drive is solid-state. And the cards will fit in your wallet, while storing the DVDs properly will eat a bunch of space.

  30. KG says

    Thanks for all the advice!

    What I’m thinking of in terms of a nuke is, as I said, a high altitude explosion – of course not likely to happen unless there’s a pretty nasty international contretemps in progress, but not necessarily life- or civilization-ending. And there’s enough of my life and work now in computer files (totalling around a terabyte) that it would be a serious personal blow to lose it. I backup regularly, and keep one copy in the garden shed in case of a fire at home that I survive but nothing inanimate in the home does, I guess I could copy everything into the “Cloud”, but I prefer not to be more at the mercy of Big Tech companies than necessary.

  31. PaulBC says

    KG@37 You could back it up on the highest capacity non-volatile memory you can come up with. I’m not sure what there is beyond DVDs at this point. While backing up a 1TB hard drive with hundreds of DVDs sounds like a pain, there is probably a lot less that you really care about keeping. Right now I’m in the tenuous position of having most of my old stuff on an external drive, though I do have DVD backups from years ago.

    DVDs may not last either. I wonder what kind of work has done on long-lasting archives, ones that would not degrade over thousands of years. They don’t have to be especially compact or fast to read back. It could be very low tech and even macroscopic: Drill holes a 1mm apart on a 1 square meter slab and you have a megabit already. Suppose it’s 1mm thick. These can be stacked compactly in large numbers (1G per cubic meter). You probably want higher density, but my point is that you can have extremely durable media and still be able to fit massive archives (terabytes in a warehouse-size building).

    I have archives going way back, but they’re organized very loosely. When switching from my undergrad to grad school and moving on from there, I remember the kinds of backups I used to make on tape media that got progressively smaller physically and larger in storage space. Everything from that period (up to 1995) could probably fit in under 250M with room to spare.

    Actually, what I really miss are the cassette tapes I made as a teen containing TRS-80 assembly language programs. I think I eventually told my family in Pennsylvania they could throw them out if they wanted. That was foolish. It hadn’t occurred to me that they would be pretty easy to recover and digitize in another form. I would be curious to see them now.

    But it’s mostly idle curiosity and if it was all lost, I suppose it wouldn’t matter. That includes personal items too, photos of my kids growing up. Obviously I would hate to lose this. I do have a lot in the cloud (as well as computer hobby work). So I think I’d be OK just having that. Work I do for an employer stays there. And that’s totally fine with me.

  32. PaulBC says

    … I guess flash drives would be a great improvement on DVD both in convenience and capacity, but my hunch is that a DVD would be more likely to survive EMP. I don’t know if that’s even true. Would a metal safe also function as a Faraday cage? Or even a gym locker? Maybe it would be effective (and very traditional) to put backups on a flashdrive and just leave that in a safe deposit box at a bank (for electronic and physical security). I’ve never gone to such effort with anything, but it’s an option.

  33. dudev says

    The Amazon listing says it measures 12″ x 9″ x 3″. It’s a file box for papers and folders with a grommet hole installed for router cables. And it costs $69. That’s probably a 200% markup from what it cost to make. Michael Faraday is rolling over in his grave, knowing he’s missing out on unbridled capitalism targeting the uneducated.

  34. says

    @PaulBC, #38/39:

    Hah, I actually took a class on preservation and there was a segment on digital stuff, so I can partially answer your question on that subject!

    Even professionally-pressed CDs, which last much longer than burned ones, have relatively poor maximum expected shelf life. No discs at all are expected to last as long as 500 years; IIRC the maximum is estimated at 300, assuming everything is perfect. This is still better than magnetic tape, which goes bad after a few decades. (And all of this is assuming best-practices storage — if you keep them in a damp basement and/or at human-comfortable temperature, they will degrade faster than that. Magnetic tape can go bad ridiculously fast.)

    If you really want to preserve digital data for the extreme long haul, what you need to do is encode it visually, print it on polyester microfilm, and keep it in a low-humidity (not 0, but somewhere around 20%, IIRC), low-temperature (again IIRC, around 10°C) darkened facility. That form is estimated to last up to 1500 years according to current materials science. (Of course, it’s less physical-space-efficient than an actual electronic medium, but at the moment we don’t have any electronic media which are estimated to last anywhere near that long.) Of course, if you write stuff out on parchment and store it properly, that has an extremely long life as well.

    SD cards (and other flash media) degrade after a decade or so if I am informed correctly, and were not covered in my course (because at the time they weren’t high-enough capacity to be interesting), but like magnetic tape can be “refreshed” a bit by actually being hooked up and read. On the other hand, if it’s a disaster recovery backup, rather than an archival backup, you don’t need long-term storage because you’ll be making new backups regularly.

    You don’t want to use flash drives in general for paranoia backups, you want specifically SD cards. Thumb drives add an extra couple of points of failure which are not easily separable from the storage itself, or easily reparable, and which receive physical stress from the act of plugging and unplugging. SD cards separate almost everything from the storage itself, so if the USB interface fails you can replace the drive but still have access to the storage. (And, incidentally, most flash thumb drives generate a vast amount of heat — for whatever reason, even external SD drives don’t seem to have such a bad problem with that.)

    SD cards might or might not survive an EMP. I can’t find any definitive answer with a quick, lazy search because most answers focus on SSDs instead and the drive mechanisms, not the storage, would definitely be toast… but of course an SD card doesn’t have those. But if you’re using them to make a regular backup because you’re being paranoid about Major Electromagnetic Events, then presumably you are already planning to alternate between two sets of backups, one of which is in a Faraday cage while the other is being created/altered anyway. (You could even put each set of backups in a small Faraday cage inside a larger Faraday cage for Extra Paranoia.)

  35. John Morales says

    Vicar (The):

    SD cards might or might not survive an EMP. I can’t find any definitive answer with a quick, lazy search

    Seriously? They’re electronic, for all that they’re non-volatile. Mostly MOSFETs — transistors.

    Anyway, DVDs do survive. As do microfiche. And paper.

    (You could even put each set of backups in a small Faraday cage inside a larger Faraday cage for Extra Paranoia.)

    You do realise if the surfaces are in contact they become essentially one surface, no?

  36. PaulBC says

    John Morales@42

    You do realise if the surfaces are in contact they become essentially one surface, no?

    I suppose you could suspend a conductive cage inside a conductive cage using an insulator. I am not sure what the point would be. The outer cage should already distribute charge so there is no electromagnetic field inside. So the inner cage doesn’t have any field left to cancel (unless there is some residual field). Maybe it would be a little different, e.g. eliminating eddy currents or something (just guessing here). It seems like a lot of trouble to go to for purposes that are unclear.

  37. PaulBC says

    @44 Well, a Faraday cage does work if the intent is to eliminate the electric field inside. There’s nothing cargo-cult about it. It’s very basic electrostatics, and the subject of demonstrations way back when in which a person inside a cage was protected from a high voltage electrical discharge. It’s also the reason people are advised to stay inside cars in a lightning storm (at least as I understand).

    It won’t protect the outside from an electrical field inside, though, which kind of debunks the tin-foil hat idea. If your brain is emitting EM signals that can be read, they will still be transmitted.

    It does take time for the electrons in the cage to regroup, so the field won’t be perfectly zero if the outside field is changing (beyond that it gets into specifics that I don’t know). I can sort of imagine the effect of nested cages being different from a single cage, given that the cage is not fully enclosed and the field inside will not be perfectly zero. It’s something that can be measured.

    Tangent: here’s some nifty electrostatics I noticed when showing my son (then 6 or 7) a simple “gold leaf electroscope”. You can make one very cheaply using aluminum foil for the gold leaf in a plastic bottle, such as for bottled water. It works great for even a small charge, e.g. like rubbing a balloon on your head. You can use a wire to transfer the charge and do a lot of cool tricks with very easily available throwaway parts.

    But it did not work at all for me when I “upgraded” to a glass bottle. Here’s what I think is happening. The aluminum foil strips are very thick compared to gold leaf and it takes a bigger charge to push them apart. It is far more likely that they were attracted to the sides of the plastic bottle, which probably had some polar molecules or what not that could align with the field. The glass bottle, being merely an insulator had no effect, so the aluminum strips were left to push each other apart the way it is supposed to work for gold leaf. They may have moved a little, but not as dramatically. It’d be interesting to revisit all this and check if my explanation is correct.

  38. says

    @#42, John Morales:

    Sorry, brain fart. Yes, of course they would melt down. I posted that right before going to bed. That’s my excuse, and I’m sticking to it. :P

    Microfiche and paper and DVDs will survive an EMP, but DVDs in particular are a bad choice overall for almost any purpose — they aren’t really long-lived enough for really long-term storage*, they have a lousy capacity-to-physical-space ratio, you have to handle them carefully to avoid scratching or smearing the surface, and they’re cumbersome for short-term backups of anything really large. You get the worst of both worlds, and spend a lot of time fiddling with their physical, uh, forms.

    *Note, however, that current best practice for most digital archivists is not “try to find a permanent medium so you can make one copy and forget about it” but “keep copying things to new media”, so in a certain sense all of this is moot.** This is more a hypothetical “if you could only make one copy to be locked away for future generations” thing.

    **This policy is also motivated by the fact that there are problems other than media degradation to be dealt with — you could pretty certainly read a CD pressed in 1995 with no problem today, but you would pretty certainly have to do some extra work to use a drive from 1995, even if it were working flawlessly after 25 years. We have no way of being sure how storage will change over the next decade, let alone over centuries. And then there are filesystems and formats — imagine trying to read a Zip disk formatted to HFS, ten years from now. And yet there were hundreds of thousands of them, possibly millions, at one time. CDs and DVDs seem safe… but who would have predicted in 1990 that in 2020 VHS would be basically unusable?

    As for surfaces of faraday cages touching: I was thinking about the truly paranoid “this must survive the end of the world” kind of thing that emergency equipment engineers and doomsday preppers go in for, because this is a hypothetical thought experiment and therefore money and trouble are not considerations. In such a case, storing all your backups in one box would be pointless, because the Death Pulse™ might show up when you have the box open to add or remove something. (After all, you would presumably need to keep making backups, right? Therefore you would need to keep accessing the safe storage to put them inside, and eventually you would run out of space and have to remove some, too.) So you would at the very least need two sets of media in two boxes… but why not have a big one that you can walk into, and then keep all the computer stuff (or whatever) in smaller ones, using shelves or cabinets to insulate them? (If nothing else, if you had some advance notice of impending doom, you could toss extra stuff into the big cage.)

  39. bcw bcw says

    Hey, as long as this is around, I’m putting everything on 5.25″ floppies!

    Now what do I do with my box of paper tape for the PDP-11? No worries about EMP.
    Though I suppose I could write some code to decode it optically using a camera…

    BTW, lightning storms are really the only reason to worry about EMP’s.

  40. whheydt says

    Re: The Vicar @ #46…
    A chemical company I worked for had a project to accumulate data on employees for term of employment plus 50 years so that they could do epidemiological studies. At one point I asked what medium was going to be used to store that data on, as (at that time) 50 years was about twice as long as commercial computers had been in existence.

  41. John Morales says

    Ray, I spent a summer with a temp job digitising tidal readings in an university.

    I got pretty fast with a keypunch, after 6 months. The ones with cylindrical keys.

    Motivating factor: there is no ‘erase’ function.

    I also got to learn how to program the keypunch. Yay?

    80 rows of 12 columns per card. Not the most information-dense medium.

    Also, spilling a deck. Laborious.

  42. steve1 says

    I will buy this for my “in box” it has a lid so no one can put anything in my inbox. Brilliant. My work is done.

  43. JustaTech says

    Several years ago I was having trouble with a blood cell counting instrument at work. And by trouble I mean that all four of the local service techs basically moved in. They replaced this piece and that, and still couldn’t get this one thing to register correctly. It was obviously an electrical problem.
    So first they ask me to clear every other device off that circuit. Still broken.
    Then they asked me to get a UPS to “clean” the power coming in from the wall. Still broken.
    Then a tech notices that there are wires outside the window. “The interference is from those wires!” (The wires were internet, and at least 20 feet away.) “But that’s just cable?” “No, those wires!” (“Those” wires were high voltage power lines, but they were more than a block away.) I expressed doubt, but he insisted, and said I needed to get a Faraday cage for the instrument.

    I laughed and laughed. “If I put it in a Faraday cage and it’s still broken can I have a new one already?” “Nope, it’s too old.”

    I did not build a Faraday cage.

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