Does a faraday bag actually work to block your phone's signal?
Worth it, if you actually fold it shut
Why you started tossing your keys in a metal tin
You toss your key fob in a metal tin by the door every night and never actually know if it's doing anything, or if you've just built an expensive paperweight. Somewhere a thief with a signal amplifier is testing exactly that gap between hope and physics. The question with any faraday bag, this one included, is whether it does faraday bag work in your pocket, or just looks like something that should.
How a faraday bag actually blocks a signal
Here's where your money actually goes: a double layer of metal fiber fabric woven into the lining, rated to block over 80dB of signal strength. That number means less on its own than what it implies, since a faraday cage doesn't destroy a signal, it redirects it. The conductive fibers form a continuous shell around your phone or key fob, and any radio wave hitting that shell gets absorbed and shunted along the fabric instead of passing through to the antenna inside. That's the same principle used in shielded rooms, just shrunk to pocket size. The catch, and the marketing skips this part, is that a faraday cage only works if it's actually closed. Fold the top over loosely and you've left a seam, and a seam is a door. Fold it flat and tuck it properly and you've sealed the shell. The bag's size, 8.2 by 4.7 inches, exists mostly to make that fold easy even with a case-covered phone or a chunky key fob, because a bag too small to fold properly is a bag that doesn't shield anything. You can check this yourself for free: put the phone inside, folded shut, and call it from another line. Silence means the shell held. A missed-call notification the second you open it means the seal did its job right up until you broke it. That's a more honest test than any spec on the listing.
So you're not buying a signal blocker, you're buying a seal. The fabric does the science, but your fold does the work. Close it right and it kills GPS, cellular, Bluetooth and RFID in one motion; close it lazily and you've bought a slightly reinforced wallet.
Who actually needs signal blocking, and who doesn't
Worth it if
- you own a keyless-entry car and want cheap relay-attack insurance
- you want a phone off-grid moment on demand without powering it off
- you carry RFID cards or a GPS tracker you want temporarily dark
- you want one pouch that also protects the phone's screen and body
Skip it if
- you expect it to block signal no matter how loosely you close it
- you need certified, lab-tested EMP or forensic-grade shielding
- you're really just shopping for a phone case and don't care about signal
Not for anyone expecting flawless blocking no matter how the bag is closed, or anyone needing certified EMP-grade or forensic shielding.
Faraday bag review: is it worth it
If you're worried about relay attacks on a keyless car, or you just want your phone off the grid at will, this is a quiet yes, provided you actually fold the thing shut. If you want a device that blocks signal regardless of how carelessly it's closed, or one built to certified EMP or forensic standards, this isn't that bag, and no bag at this price is.
Fold it right once and the nightly key-fob shuffle stops being a question mark. Day one looks like this: key fob goes in, folded flat, and you stop half-listening for the car alarm overnight. Phone goes in during a meeting and it's actually offline, not just on silent. A large number of buyers mainly praise it for fitting big phones well and protecting them from scratches, though how consistently it blocks signal seems to depend on that same fold you now know matters.
Amazon shoppers rate it 4.4 out of 5 across 2,373 ratings. That is their number, not ours.
Before you go
What are the disadvantages of Faraday bags?
The main disadvantage is that shielding only works if the bag is fully and properly closed, a loose fold leaves a gap signal can leak through, and cheaper fabric can wear down with repeated folding.
Can a cell phone be tracked in a Faraday bag?
No, not while it's properly sealed inside, since the shell blocks the phone from sending or receiving the GPS and cellular signals tracking depends on; the moment it's opened, tracking resumes.
Will aluminum foil work like a Faraday bag?
Foil can block signal in a rough sense, but it creases, tears, and loses its seal fast, while a woven metal fiber pouch holds its shielding shape through daily folding.
Does TSA allow Faraday bags?
Yes, TSA allows Faraday bags in carry-on and checked luggage, though agents may ask you to open one during screening since the shielding blocks the X-ray view inside.
By the numbers
Like 100% of the 17 phones & accessories products we've reviewed, this one earns a conditional "worth it, but" — none have cleared our unconditional top tier yet. All verdicts are published as open data in the Is It Worth It Reviews Verdict Dataset (CC BY 4.0).
Full spec sheet
| Handle Type | Top handle |
|---|---|
| Number of Compartments | 2 |
| Color | Black |
| Style Name | Pouch |
| Pattern | Solid |
| Item Weight | 0.16 kg |
| Size | M(Up to Phone) |
| Material Type | shielded metal fiber |
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