A Faraday bag has one test and it costs nothing: seal your phone inside and call it from another phone. If it rings, the bag failed — today, with that closure, that phone. That is the whole verdict on the everyday job (key-fob relay theft, tracking, a phone that must stay unreachable). The EMP job is different. CISA describes a high-altitude EMP attack as low probability and high consequence, and its protection guidelines are written for infrastructure enclosures with measured shielding; none of the consumer bags below states a shielding figure, so treat “EMP-proof” on a listing as a hope, not a spec.
Six pouches and sets compared on what the listings say — material, closure, sizes — with the catch for each and the test to run the day it arrives. No scores, no prices. For the broader question of what an electromagnetic pulse would and would not do to a household, our guide on protecting devices from an EMP covers the physics and the cheaper alternatives (a metal ammo can, a sealed steel box).
What a bag can do, and the two jobs people confuse
- Radio isolation (works, testable). A sealed conductive pouch stops the phone talking to towers, Wi-Fi, Bluetooth and GPS, and stops a key fob answering a relay device. You can prove it in ten seconds with a call, a Bluetooth speaker, or by trying the car door.
- EMP protection (unverified on consumer bags). An EMP is a very fast, very strong pulse over a broad band of frequencies. Shielding against it is specified in decibels of attenuation across that band and depends on seams and closures as much as material. CISA’s EMP guidelines exist for critical infrastructure; a pouch that does not publish an attenuation figure has not been tested against it. A bag that fails the phone test fails both jobs.
- The closure is the product. Every failure mode is a gap: a roll-top folded once instead of three times, a hook-and-loop strip not pressed down, a cable poking out. Buy for the closure, then test it.
At a glance
| Product | Best for | Material / closure / count (listing) |
|---|---|---|
| Mission Darkness non-window phone bag | The reference pouch for one phone, or a phone and a fob | RF liner / double Velcro / 1 |
| Simket Faraday pouches, 2-pack | A phone and a car key, every night by the door | Metal fibre / roll top / 2 |
| Xiaodun dual-compartment Faraday pouch | Phone in one side, key fob and cards in the other | Triple layer / two compartments / 1 |
| Yaokvide Faraday bags, 5 sizes | Phone, tablet and laptop in one set | Fibreglass / hook & loop / 5 |
| Coorattyes Faraday set with key-fob sleeve | A family set: devices plus the fob | TPU / assorted / 5 + fob |
| ZapEnergi pouches with belt clip, 2-pack | The budget pair for phone and fob | Not stated / clip / 2 |
Mission Darkness non-window phone bag
For: The reference pouch for one phone, or a phone and a fob
What the listing says: Nylon exterior with an RF-blocking liner, double roll-and-Velcro closure, water resistant, sized for any phone.
Before you buy: Non-window means you cannot see the phone; that is the point — windows are a shielding compromise. One bag, one phone: buy two if you want the fob isolated at the same time.
Simket Faraday pouches, 2-pack
For: A phone and a car key, every night by the door
What the listing says: Two pouches with a shielded metal-fibre liner, top handle, fits phones in cases.
Before you buy: Roomy enough for a cased phone, which also means a loose fit for a key fob; fold the top the full number of turns or the fob will still answer the relay. Run the door test, not just the phone test.
Xiaodun dual-compartment Faraday pouch Sponsored
For: Phone in one side, key fob and cards in the other
What the listing says: Two independently shielded compartments, two card slots, triple-layer shielding fabric, listed as fireproof and waterproof exterior.
Before you buy: Two compartments means two closures to get right; test each side on its own (phone in one, fob in the other, then swap). “Fireproof” means the outer fabric resists flame, not that a phone survives a house fire inside it; keep documents in a rated fire bag.
Yaokvide Faraday bags, 5 sizes
For: Phone, tablet and laptop in one set
What the listing says: Five fibreglass-shielded bags in assorted sizes with hook-and-loop closure.
Before you buy: A laptop-size bag has a long closure, and a long closure is where the gaps live. Test the big one with a phone inside before trusting it with the laptop, and re-test after a few months of use.
Coorattyes Faraday set with key-fob sleeve
For: A family set: devices plus the fob
What the listing says: Five TPU-shelled pouches in assorted sizes plus a key-fob protector.
Before you buy: The fob sleeve is the item most households actually use nightly; the large pouches will sit in a drawer. If the fob is the reason, a dedicated two-pack is cheaper and the same protection.
ZapEnergi pouches with belt clip, 2-pack
For: The budget pair for phone and fob
What the listing says: Two pouches with belt clip and lanyard option, listed as waterproof and RFID blocking.
Before you buy: The listing does not state the shielding material. That is not disqualifying — the phone test is — but it means you are testing, not trusting. Very bulky cases may not seal fully.
The test, and when to repeat it
- Phone inside, screen on, volume up. Close the bag exactly as the instructions say — three folds, every strip pressed.
- Call it. Send a message. Try to find it in a Bluetooth list. Nothing should get through.
- For a key fob: seal it, walk to the car, try the handle. Then try with the fob three feet from the car in the bag.
- Repeat every few months and after any fraying; shielding fabrics crease and closures wear.
What to keep in one, and what not to bother with
Worth isolating: the car key at night (relay theft is the everyday attack), a spare phone kept for emergencies with its battery half charged, a small backup drive with the family documents. Not worth it: the phone you use every day (it spends its life outside the bag), and anything you would need instantly in a crisis. For a household EMP plan, the question is which handful of devices you would want working afterwards — a radio, a spare phone, a power bank — and our EMP guide covers the metal-container alternative for those. For the far more likely event — a long ordinary blackout — the blackout guide is the page to read first.
FAQ
Do Faraday bags actually work?
For blocking radio signals, yes when sealed correctly, and you can verify it with a phone call. For EMP, consumer bags are untested unless the maker publishes attenuation figures; treat that claim as unproven.
How likely is an EMP?
CISA classifies an intentional high-altitude EMP as a low-probability, high-consequence event. A long grid outage from weather is the far more common failure and needs the same batteries, radios and water either way.
Can I make my own?
A metal box with a tight lid and an insulating layer inside (cardboard, so the device does not touch the metal) does the same radio-blocking job for stored devices. A bag is more convenient for a phone you carry.
Preparing with Dan is reader-supported: as an Amazon Associate we earn from qualifying purchases. Products marked “Sponsored” (Xiaodun) take part in Amazon Creator Connections, a programme in which the brand pays us a higher commission on those links; it does not change our assessment or the order of this list. Product details are as stated on the retailer listings at the time of writing; check the listing before you buy.
Official sources & further reading
The guidance in this article comes from official sources. Consult them directly for the authoritative version:
Dan Lockland is a preparedness instructor and survival skills educator with over 15 years of hands-on experience. He shares practical, no-nonsense guidance on emergency preparedness, self-reliance, and sustainable living at PreparingWithDan.com.