Best Faraday Bags in 2026, by Use

Last verified November 2, 2026. Prices and specs come from the maker or a named retailer on that date. Shielding figures are the brands' own unless we name an independent tester.

We have not measured these bags ourselves; test results come from the people named below.

The short answer

A Faraday bag is a pouch lined with conductive fabric. Sealed properly, it stops most radio signals getting to or from what is inside: cellular, Wi-Fi, Bluetooth, GPS and car key fobs. People use them for privacy, to put a phone out of reach while they focus, and to stop thieves relaying a keyless car fob's signal. They reduce signals rather than guarantee zero, so test yours before you rely on it¹. For phones, the Mission Darkness Non-Window bag ($23) is the cheapest well-tested option; for key fobs, a $15 Mission Darkness 2-pack or a magnetic-closure pouch works if you test it on your own car^{2, 4, 5, 8}.

What a Faraday bag does, and doesn't

A closed conductive shell blocks radio waves from passing through it. That is the idea behind a Faraday cage, and a Faraday bag is a flexible version: layers of metallized fabric with a closure that rolls, folds or clamps shut. Forensic investigators use them to cut seized phones off from the network¹.

• It does stop a sealed phone from connecting to cell towers, Wi-Fi and Bluetooth, and from getting GPS, when the bag and closure are in good shape^{2, 5}.
• It does stop a thief's relay box from picking up a keyless car fob in the pouch, which is how relay thefts work⁴.
• It doesn't block perfectly every time. NIST's forensic guidance says Faraday containers "may attenuate the radio signal, but not necessarily eliminate it completely", especially near a cell tower¹.
• It doesn't protect data you have already shared, or anything the phone does when it is out of the bag.
• It drains the battery. A phone that can't find a network raises its transmit power to keep searching¹. Switch to airplane mode or power off if you'll leave it sealed for long.

Some listings also say their bags reduce "EMF radiation" exposure^{5, 7}. That is a different question from signal blocking, and this page doesn't rate bags on it. We judge them only on how well they block signals and how easy they are to use.

What independent testing shows

Grades for each claim: A repeated independent lab tests to a stated standard. B independent hands-on tests. C informal or single tests. D brand claims only.

Claim	Grade	Best evidence
Commercial phone pouches block cellular and Wi-Fi when sealed	B	Security researcher Matt Blaze found the EDEC OffGrid and Mission Darkness Window pouches gave "excellent performance" in the bands he tested2. NIST notes forensic shielding can still let some signals through, SMS most often1.
Key fob pouches stop keyless car theft by relay	B	Auto Express tried to open and start three keyless cars with fobs in seven pouches. All blocked the signal, before and after a simulated 18 months of wear; some leaked faintly when overfilled or carelessly fastened4.
Phone bags block all signals in all conditions	C	An informal Wi-Fi test found SLNT and Disklabs bags cut signal by roughly 55 and 65 dB but leaked when the phone was rotated or moved, and how the lid was closed changed the result3.
DIY foil works as well	C	Foil sometimes matched commercial pouches in Blaze's tests, but only in ideal conditions2; another tester found foil degraded with use3.
"Tested to MIL-STD-188-125 and IEEE 299"	D	Brands cite these standards5, 7, but the pages we checked didn't name the lab or publish the report. The tests usually cover the fabric, not the finished bag and its closure. Ask for the report.

How to test a Faraday bag at home

NIST tells forensic examiners to test their own shielding before relying on it¹. You can do a simple version:

1. Calls. Turn the phone's ringer on, seal it fully, and call it from another phone. Wait at least 30 seconds. It should go straight to voicemail or not ring.
2. Texts and data. Send it a text and a message from an app. Texts are the signal most likely to get through¹. Check when you take it out whether anything arrived while it was sealed.
3. Wi-Fi and Bluetooth. Stand next to your router, or stream music to Bluetooth headphones, then seal the phone. The music should stop.
4. Key fobs. Seal the fob in its pouch, hold it against the car door handle and try to open the door and start the car. Test the way you will really use it: with the keys you carry, closed the way you'll close it in a hurry⁴.
5. Worst case. Try different orientations and stand closer to the router or a window. Bags that pass in one position can leak in another³.
6. Retest. Linings wear. Repeat the test every few months and after any rip or crease near the opening^{3, 4}.

How we picked

1. Independent testing of the brand or model where it exists, named above.
2. A closure that seals across the full opening (roll-down, fold-and-tuck or magnetic).
3. Sold in the US on November 2, 2026 with a published price from the maker or a named retailer.
4. Commission plays no part. Some links below earn us a commission and some don't.

Picks for phones

Best value: Mission Darkness Non-Window

$23 for a bag with an 8.5 by 5 inch interior, big enough for most phones in a case. You roll the top down twice and press the hook-and-loop strip shut across its full width. MOS Equipment says the fabric is certified to MIL-STD-188-125 and IEEE 299-2006 from low MHz to 40 GHz, with reports on request⁵. Matt Blaze tested the windowed version of this bag and rated it excellent². There is no window, so you can't see the screen while it is sealed.

Price checked November 13, 2026

Everyday carry: OffGrid Faraday Bag - Mobile

$35. A single fold closes with hook-and-loop backed by a magnet, which is quicker than a double roll⁶. OffGrid (made by EDEC) was the other pouch Matt Blaze rated excellent, though the report doesn't say which OffGrid model he used². OffGrid doesn't publish shielding figures on the listing we checked⁶.

Price checked November 13, 2026

Slimmest: SLNT Faraday Phone Sleeve

From $79.95 in Medium (6.7 by 4.5 inch interior) and Medium Plus (7.6 by 4.8 inch), in nylon or leather, with a magnetic closure. It is the neatest-looking option here. SLNT claims 100 dB+ blocking⁷. One informal test measured about 55 dB on Wi-Fi and found it leaked when the phone was moved or rotated, and that the closure mattered³, so test it in the way you'll use it.

Price checked November 13, 2026

Picks for car key fobs

Cheapest: Mission Darkness Faraday Bag for Keyfobs (2-pack)

$15 for two pouches with a 4.5 by 3 inch interior and a fold-and-tuck closure under an elastic band, made from the same fabric as the phone bag⁸. Two pouches means one for each fob. Check your fob fits with the top folded fully over.

Price checked November 13, 2026

Magnetic closure: Faraday Defense Jacket key fob bag

$19.99 at TriTech Forensics and $21.99 from Faraday Defense on November 3, 2026 (price checked November 3, 2026)¹⁰, with a 4.75 by 2.75 inch interior and a double-fold magnetic closure. Faraday Defense claims over 85 dB from 400 MHz to 40 GHz but doesn't cite a standard⁹. Auto Express found magnetic fasteners can pop open on bulky keys⁴, so make sure yours closes flat.

Price checked November 3, 2026

Specs and prices

Price checked November 2, 2026.

Bag	For	Interior	Closure	Shielding claim	Independent test	Price
Mission Darkness Non-Window5	Phone	8.5 x 5 in	Double roll, hook-and-loop	MIL-STD-188-125, IEEE 299 (fabric)	Windowed version rated excellent by Matt Blaze2	$23
OffGrid Mobile6	Phone	Not stated	Single fold, magnet	Not stated	OffGrid pouch rated excellent by Matt Blaze; model not named2	$35
SLNT Faraday Phone Sleeve7	Phone	6.7 x 4.5 in (M)	Magnetic	100 dB+	About 55 dB on Wi-Fi, leaked in harder positions (informal)3	From $79.95
Mission Darkness Keyfobs 2-pack8	Key fob	4.5 x 3 in	Fold and tuck	MIL-STD-188-125, IEEE 299 (fabric)	None found	$15
Faraday Defense Jacket key fob9	Key fob	4.75 x 2.75 in	Double fold, magnet	Over 85 dB, 400 MHz to 40 GHz	None found	$19.99 (TriTech); $21.99 (Faraday Defense)

We dropped GoDark and the FaradayBag.com PS1 from the previous version of this page because we couldn't confirm current prices or find independent tests.

Other ways to stop relay theft

• Keep fobs away from doors and windows at home, in a pouch or a metal box you have tested.
• Check your car's manual: some fobs can be switched to a sleep mode or have keyless entry turned off.
• A visible steering lock is a second layer that doesn't depend on radio.

Myths

• "A Faraday bag makes you untraceable." Only while the device is sealed. It doesn't erase where the phone has been or what it has shared.
• "The highest dB figure wins." Brand figures usually describe the fabric. Closures and wear decide real-world results^{3, 4}.
• "Any foil wrap works." Sometimes, in ideal conditions, but not reliably².

FAQ

Do Faraday bags actually work?

Good ones block most signals when sealed properly. Independent tests found commercial phone pouches and key fob pouches effective, with leaks from poor closure, overfilling or wear^{2, 3, 4}. Test yours.

Will I miss calls with my phone in a Faraday bag?

Yes. That is the point. Calls and texts arrive when you take it out, if your carrier holds them.

Does a Faraday bag drain the battery?

It can. A phone that can't find a network increases its power while it searches¹. Use airplane mode or switch it off for long periods.

Can a Faraday bag help me focus?

It is a firm way to make a phone unreachable during work or training. Airplane mode does much the same for free; a bag adds a physical barrier and removes the temptation to switch it back.

Is an RFID wallet the same thing?

Not quite. RFID-blocking wallets target contactless cards at 13.56 MHz. Phone and fob pouches claim much wider ranges^{5, 7, 9}. Test any pouch with your own car fob.

Can I make my own?

You can, but DIY shields performed inconsistently in the tests we found, and foil wore out with use^{2, 3}. A commercial pouch costs $15 to $35.

How long do key fob pouches last?

Auto Express's pouches all still blocked after a simulated 18 months of use⁴, but linings crease and wear. Retest every few months.

Related guides

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References

Brand and retailer pages were checked on November 2, 2026.

1. Ayers R, Brothers S, Jansen W. Guidelines on mobile device forensics. NIST Special Publication 800-101 Revision 1, May 2014. Section 4.3 (isolation): Faraday containers "may attenuate the radio signal, but not necessarily eliminate it completely"; radio-isolated phones raise transmit power and drain the battery; examiners "should test their own products"; a Purdue test found SMS messages most often got through. Source
2. Boing Boing. Phone-sized Faraday bags tested (2 December 2021), reporting security researcher Matt Blaze's tests of six pouches: the EDEC OffGrid and Mission Darkness Window pouches performed excellently; no DIY option did consistently as well; foil worked only under ideal conditions; a cookie tin failed. No dB figures or method details published. Source
3. stiankri. Faraday shield effectiveness (Substack, undated). Informal Wi-Fi test with a Pixel 7 Pro and a 2.4/5 GHz router: Disklabs about 65 dB, SLNT about 55 dB, DIY foil about 54 dB; both commercial bags leaked under harder conditions; closure affected results; the author calls the figures "not at all rigorous". Source
4. Auto Express. Best Faraday bag car key signal blockers (29 January 2026). Pouches tested by trying to open and start three keyless cars, before and after 1,200 tumbles to simulate wear; all seven blocked the signal, with small leaks when overfilled or carelessly closed. Source
5. MOS Equipment. Mission Darkness Non-Window Faraday Bag for Phones: $23; 8.5 x 5 in usable interior; double roll-down closure with hook-and-loop; fabric "lab tested and certified to MIL-STD 188-125 and IEEE 299-2006", low MHz to 40 GHz; lab not named, reports on request. Checked 2 November 2026. Source
6. OffGrid. OffGrid Faraday Bag - Mobile, brand storefront listing: $35; single-fold hook-and-loop seal backed by a magnetic closure; multiple layers of Faraday material; no test figures stated. Checked 2 November 2026. Source
7. Tactical Distributors. SLNT Faraday Phone Sleeve: from $79.95; Medium internal 6.7 x 4.5 in, Medium Plus 7.6 x 4.8 in; magnetic closure; brand claims 100 dB+ and MIL-STD-188-125-2 / IEEE 299-2006 (1 to 40 GHz) compliance. Checked 2 November 2026. Source
8. MOS Equipment. Mission Darkness Faraday Bag for Keyfobs, 2-pack: $15; 4.5 x 3 in usable interior; fold-and-tuck closure under an elastic band; same fabric certification claims as above. Checked 2 November 2026. Source
9. TriTech Forensics. Faraday Defense Jacket Faraday Anti-Theft Key Fob Dry Bag: $19.99; 4.75 x 2.75 in interior; double-fold magnetic closure; brand claims over 85 dB from 400 MHz to 40 GHz; no standard cited. Checked 2 November 2026. Source
10. Faraday Defense (JBS store). JACKET Faraday Anti-Theft Key Fob Dry Bag: $21.99; 4.75 x 2.75 in interior; double-fold magnetic closure; ">85 dB" (the page gives both 400 MHz to 40 GHz and 400 MHz to 4 GHz). Checked 3 November 2026. Source

Header photo by Jose G. Ortega Castro on Unsplash.