Faraday Box for Keys: Complete Guide
If you own a modern vehicle with a key-fob or keyless entry system, you may have heard of the term “Signal Blocking Faraday Safe Box for Wireless Car Key Fobs” or more generally a Faraday box for keys. At its core, this is a small enclosure—essentially a miniature version of a Faraday cage—designed to block electromagnetic signals coming to or from your key fob.
In plain language: you place your key (or key-fob) inside the box, and it prevents thieves from capturing or relaying the signal that your key sends to your car. As key‐less/remote systems become more common, the Faraday box becomes an increasingly relevant security accessory.
This article covers what a Faraday box is and all the frequently asked questions around it—how it works, when you should use it, what to look for when choosing one, limitations, DIY options, and more.
What Is a Faraday Box for Keys?
A Faraday box for keys (or Faraday pouch, Faraday bag) is a container lined or constructed with conductive material (metal mesh, foil, or conductive fabric) that blocks electromagnetic waves from passing through. As applied to car key-fobs and smart keys:
- It prevents the key’s wireless signal from being amplified or relayed by thieves.
- It blocks RFID/NFC/GPS/remote entry signals from the key when placed inside.
- It uses the same principle as a Faraday cage: external electromagnetic fields cause charge redistribution in the conductive shell, which cancels the field inside.
Why it’s important for key-fobs
Modern vehicles often use wireless key‐fobs that emit a low‐power signal to unlock/lock or start a vehicle when in proximity. Criminals exploit this by doing “relay attacks” whereby they boost the signal from the key (inside a house, for example) and relay it to a receiver near the car, tricking the car into thinking the key is present.
By placing the key inside a Faraday box, you thwart the relay because the signal can’t escape or be intercepted.
How Does It Work? (Explained Simply)
- You put your key / fob into the Faraday box for keys and close it.
- The conductive lining of the box intercepts or reflects incoming/outgoing RF (radio frequency) signals so the key cannot transmit or receive electromagnetic communication.
- With the key “silent,” thieves can’t pick up or amplify its signal to unlock or start your car.
- When you take the key out of the box, it functions normally again.
In effect, the Faraday box disconnects the key wirelessly, even though the key remains physically stored.
This is why reviewers call it a “mini Faraday cage for your key fob”.
Who Should Use One?
You should strongly consider a Faraday box for your key if:
- Your car uses keyless entry or key-fob systems (push-button start, remote unlocking)
- You park your car at home, especially near a window or exterior wall (easy access for thieves)
- You live in an area with reports of keyless car thefts or relay attacks
- You carry spare key-fobs inside your house or near doors/windows
- You want extra peace-of-mind security beyond locks and alarms
In news coverage, experts recommend “keep your key fob inside a Faraday pouch or box whenever the vehicle is parked.”
Key Questions People Ask
- The faraday box for keys must fully enclose the key with minimal gaps.
- The conductive material quality matters.
- You should test it: after placing your key in the box, try walking near your car — if the doors don’t auto-unlock, then the signal is effectively blocked.
2. Can I just use aluminium foil or a tin instead of buying one?
Yes, you can, but results vary. Some articles note that a metallic tin may block the signal, but not all do reliably.
Pros of DIY: very low cost.
Cons: uncertain effectiveness, may be inconvenient, may damage key if misused (e.g., putting in microwave or wrapping wrong). News outlets caution against random methods like microwave.
3. What features should I look for when buying a faraday box for keys?
When selecting a Faraday box for keys, consider:
- Size: Must fit your key / fob comfortably (and spares if needed)
- Shielding quality: Look for conductive fabric or metal lining, sealed seams
- Closure: Zipper or magnetic/snap closure that ensures full coverage
- Durability & design: If you’ll keep it near entryway or travel with it
- Testing guarantee: Some brands show whether signal is blocked
- Portability: If you want to carry it in bag or glovebox
Here are some good examples:
GoDark Vault Key Fob Faraday Cage
$49.00
•
GoDark Faraday Box for Keys+ others
Signal Blocking Faraday Safe Box for Wireless Car Key Fobs
$25.00
•
Burger Motorsports + others
Mission Darkness Faraday Box for Keys fobs
$15.00
•
Mission Darkness + others
briidea Faraday Box Key Fob Protector
$23.99
•
Walmart – Seller + others
Carevas Faraday Box Key Fob Protector 2‑Pack
$29.39
•
Walmart – jiezuchuan
JXE JXO Faraday Box Car Key Fob Protector
$31.36
•
Sears – zabiva + others
Kenark KK7 Plus‑BK Faraday Box for keys
$91.49
•
Sears – zabiva + others
Faraday Box Carbon Fiber Texture Keyless Fob Protector
$18.99
•
Walmart – LECHENG-Healthy Living Store
Here’s a quick summary of each:
- GoDark Vault Key Fob Faraday Cage – premium metal enclosure, durable, good for home entryway.
- Signal Blocking Faraday Safe Box for Wireless Car Key Fobs – purpose-built safe box for car key fobs, mid‐price.
- Mission Darkness Faraday Bag for Keyfobs – bag rather than hard box; good portability.
- briidea Faraday Box Key Fob Protector – stylish look, PU leather, budget friendly.
- Carevas Faraday Box Key Fob Protector 2‑Pack – affordable two‐pack, good if you have multiple key fobs.
- JXE JXO Faraday Box Car Key Fob Protector – wood finish, aesthetic option.
- Kenark KK7 Plus‑BK Faraday Box – high‐end anti-clone key fob box with added features.
- Faraday Box Carbon Fiber Texture Keyless Fob Protector – economy, carbon fiber look, compact size.
4. How much do they cost?
Costs vary quite a bit depending on materials, size, brand, etc.: from ~$20 up to $50+ for premium metal enclosures. (See product list above for examples.) For many users the investment is modest compared to the value of protecting a vehicle.
5. Where should I keep the Faraday box for keys in my home or car?
- At home: Keep it close to where you normally store your key / fob when you arrive (entryway, nightstand, dresser).
- Avoid placing it near windows or doors where the key’s signal might still be captured (even if inside box, signals may leak if box is open).
- In your car: Some people keep a Faraday box in the car glovebox and place the spare fob inside when parking. Others use it for “key lockup” when vehicle is parked long‐term.
- Travel: If staying overnight somewhere unfamiliar, you might place your key inside the box in the hotel safe or drawer to reduce risk.
6. Will placing my key in a Faraday box affect normal use?
When properly used, no — when you take the key out, everything works as usual. However:
- If your key stays inside the box and you walk to your car expecting auto-unlock, it won’t unlock until key signal is available. That means you have to take the key out before walking to the car.
- If you keep the key inside the box too long (for example inside car when driving) you might disable remote start or unlock features while inside the box.
7. Are there limitations or things they don’t protect?
Yes. Important limitations include:
- They only protect the key signal. They don’t stop physical theft of the key, theft via other vulnerabilities in the car (e.g., hacking through CAN bus), or theft of other items via force.
- The box must be closed completely and made from sufficiently conductive material. Gaps, poor materials, or open seams reduce effectiveness.
- They don’t prevent every type of attack—some advanced attacks might bypass key signal entirely (though far less common).
- Some claims require users to remember to always use the box. If you forget to put the key inside, you’re exposed.
- Cars older than key-fob systems may not benefit as much.
- If you use the key inside a pouch or box during driving, the car may lose remote key functions or shut off unintended features.
8. Can I make my own Faraday box for keys ?
Yes. Many people have fashioned DIY Faraday cages using metal tins, foil-lined boxes, or metal containers. For example:
“A Faraday box acts as an interrupter for radio frequencies, so putting your car keys into it can block the criminals from unlocking & making off with your ride.” Reddit
“Storing a car key fob in a metallic tin MAY prevent keyless car theft… we recommend testing first to check if the signal is blocked.” Master Locksmiths Association
But DIY comes with caveats: you must test that the key’s signal is actually blocked (walk to car and ensure auto-unlock doesn’t trigger). And you may lose convenience or aesthetics compared to commercial solutions.
9. How do I test if the Faraday box works?
Simple method:
- Take your key/fob and bring it close enough to your vehicle until it would normally unlock the doors automatically (or you press lock/unlock).
- Then place the key inside the closed Faraday box.
- Walk the same distance to the car and see if it still unlocks the doors automatically (or responds to key). If it does not, the box is likely doing its job.
Experts advise doing exactly this test.
10. What about signal jamming or trackers?
Using a Faraday box helps block the key’s outgoing/incoming signal, so trackers inside the key or interception of the key’s signal are far less likely. But note: other methods of theft (GPS trackers placed on car, physical hacking) are not prevented solely by a box. Some articles cover remote jamming or remote hacking of cars via signal amplification.
11. Is a Faraday box only for car key-fobs?
No. While this article focuses on keys, the same principle applies to other wireless devices: RFID cards, credit cards, smartphones, tablets, trackers. If the device emits or receives wireless signals you want to block, a Faraday enclosure can work. Many Faraday pouches cover phones and tablets too.
12. Can insurance or warranty cover theft if I use one?
This depends on your insurer/policy. Some insurers may view using such a protective device as a positive security measure, which could help if you make a theft claim (showing you took steps to secure your key). But this is not guaranteed. It’s best to check your auto insurance and home insurance terms. Using a Faraday box is a preventive measure, not a guarantee of theft avoidance.
13. How often should I replace or inspect my Faraday box for keys?
- Inspect the closure mechanism (zipper, magnet) to ensure it closes fully and securely.
- Check for damage to the conductive lining (torn fabric, exposed seams).
- If the box becomes warped or deformed (especially metal ones), it may lose effectiveness.
- Replace if you notice your key still unlocks the car while inside the box. That is a clear sign of failure.
Practical Steps: How to Use a Faraday Box for Keys
Here’s a simple “how-to” process:
- Choose a Faraday box sized appropriately for your key/fob(s).
- Place your key in the box each time you park your vehicle or when it’s not in use.
- Keep the box in a consistent location (entryway drawer, nightstand, glovebox) so you don’t forget.
- After placing the key in the box, test it occasionally to verify it still blocks signal (walk near car, try auto-unlock).
- Do not store the key inside the box if you plan to use it immediately or carry the key to your car while the box is closed—take it out before walking to your car.
- If you have spare key-fobs (e.g., valet key, second car), keep them also inside a Faraday box when not in use.
- Combine this with other vehicle security practices: park in well-lit area, use steering wheel locks, ensure car software and locks are up to date.
- When traveling or staying overnight somewhere new, place your key inside the box inside your room or safe for added security.
Common Mistakes & FAQs
- Mistake: Leaving the key outside the box “just for convenience.”
Consequence: You’re vulnerable to signal theft/relay attacks. - Mistake: Relying solely on the box and neglecting other security measures (alarms, physical locks, software updates).
Consequence: You may block one attack vector, but leave others open. - FAQ: “Will it stop someone with a signal booster from amplifying my key?”
Answer: Yes—if the key is inside the fully enclosed, properly functioning box, the signal cannot escape to be amplified. - FAQ: “Does the car’s keyless system get interfered with while driving if I keep the key inside the box in the car?”
Answer: Yes—many cars rely on the key’s signal inside the cabin. If the key remains inside a box that blocks all signal while driving, you may lose remote features or ignition recognition. So typically you remove the key from the box before driving. - FAQ: “Will storing my key in a Faraday box drain the key battery?”
Answer: Not significantly. The key’s transmitter is still present but its signals are blocked. The battery usage by the key will remain largely unchanged—what changes is whether the signal is accessible. - FAQ: “Is this needed if my car doesn’t have push-button start?”
Answer: If your car uses a standard “insert key in ignition” mechanical key system, then the threat of relay attacks is much lower—but if your key still has remote unlocking, you may still benefit. For keyless push-start vehicles, the risk is higher. - FAQ: “If I wrap the key in foil and store it in a drawer, is that enough?”
Answer: It might provide some protection, but reliability is uncertain. Many experts recommend certified Faraday boxes or pouches rather than improvised solutions. In particular, test whether the key’s signal is actually blocked.
✅ Recommended For Your Faraday Box with Keys
GoDark Vault Key Fob Faraday Cage
$49.00
GoDark Faraday Bags + others
Signal Blocking Faraday Safe Box for Wireless Car Key Fobs
$25.00
Burger Motorsports + others
Mission Darkness Faraday box for keys and Keyfobs
$15.00
Mission Darkness + others
SLNT Faraday Key Fob Bag
$21.95
SLNT + others
briidea Faraday Box for keys Key Fob Protector
$23.99
Walmart – Seller + others
Carevas Faraday Box Key Fob Protector 2‑Pack
$29.39
Walmart – jiezuchuan
JXE JXO Faraday Box Car Key Fob Protector
$31.36
Sears – zabiva + others
Car Key Faraday Bags (Economy)
$7.99
Walmart – Seller
Quick comparison (10 picks)
| Product | Type | Typical price (USD) | Notable specs / dimensions | Best for |
|---|---|---|---|---|
| GoDark Vault | Hard box (solid aluminum) | ~$49 | 2.1 mm aluminum; blocks 315 MHz & 433.92 MHz + Wi-Fi/Bluetooth/GPS; magnetic closure. | Maximum protection & durability |
| Mission Darkness Keyfob (2-pack) | Fabric pouch | ~$15 | Keyfob-size bag; designed to prevent relay hacking; holds 1–2 fobs. | Reliable value, two pouches |
| SLNT Key Fob Bag | Fabric pouch | ~$22–30 | Multishield® lining; XS/Small sizes; XS internal ~4.33″×3.54″. | Sleek EDC carry |
| DefenderShield Key Fob Bag | Fabric pouch | ~$32–40 | “Ultra Armor” Faraday bag; blocks wide RF range (maker claim). | Brand-name privacy gear |
| TICONN 2-Pack | Fabric pouches (2) | ~$10–22 | 3.5″×5″ class carbon-fiber-style pouches; popular budget choice. | Cheapest decent starter |
| briidea Faraday Box | Hard box (PU leather exterior) | ~$22–24 | Stores multiple keys; RF-shielding lining. | Entryway storage & looks |
| Burger Tuning Faraday Box | Hard box | ~$25 | “Zero signal in/out” safe-box for car keys. | Garage/gearhead crowd |
| Faraday Defense Key Fob Dry Bag | Fabric pouch (weatherproof) | ~$20 | Rugged, RF-blocking key pouch for outdoor use. | Camping, work sites |
| Koruma Faraday Box (Etsy) | Hard box (large) | ~$58 | Large interior (~14.5×10.5×7.5 cm) for keys + wallet/phone. | Keys + wallet/phone together |
| Generic Budget 2-pack | Fabric pouches (2) | ~$8–20 | No-frills key-fob pouches from marketplace sellers. | Ultra-cheap trial option |
What to pick (fast)
- Want the safest, longest-lasting option? Go GoDark Vault (hard metal box).
- Want good protection for less and a pocketable form? Mission Darkness or SLNT pouches.
- Want an entryway box that holds several keys and looks nice? briidea or Koruma.
- On a tight budget? TICONN or a generic 2-pack—just test them against your car.
How to test any of these faraday box for keys (takes 30 seconds)
Put your fob inside, close it fully, and try to unlock your car from a distance where it normally works. If the car still responds, that container isn’t doing its job. (Experts specifically recommend this simple test.)
And here’s a breakdown of each:
- GoDark Vault Key Fob Faraday Cage: premium build, solid aluminum, magnetic closure, covers full frequency range (315 MHz, 433.92 MHz, WiFi, Bluetooth, GPS) according to manufacturer.
- Signal Blocking Faraday Safe Box for Wireless Car Key Fobs: mid-price (~$25) safe-box style, intended for car keys.
- Mission Darkness Faraday Bag for Keyfobs: bag rather than hard box; reputable brand with three-layer shielding fabric.
- SLNT Faraday Key Fob Bag: sleek, sleeve style, focuses on portability and subtle design.
- briidea Faraday Box Key Fob Protector: stylish PU leather box, budget friendly (~$23.99) good for multiple keys.
- Carevas Faraday Box Key Fob Protector 2‑Pack: very budget-friendly two-pack (good if you have spare keys).
- JXE JXO Faraday Box Car Key Fob Protector: wood finish novelty/higher end aesthetic box (~$31)
- Car Key Faraday Bags (Economy): ultra-budget (~$7.99) option—less premium materials, but could suffice if testing the concept.
🧠 How to Choose Your Faraday Box For Keys (and What to Prioritize)
Based on expert commentary and testing:
Key criteria
- Signal blocking effectiveness: The enclosure must fully block the RF/EM signals from the key-fob. If your car continues to auto-unlock while the key is in the box/pouch, the shielding is insufficient. carwow.co.uk+1
- Closure quality & no gaps: Even small gaps, worn seams, thin material will compromise effectiveness. DIY foil/rusty tins may fail. Howden Insurance+1
- Size & fit: The box/pouch must accommodate your specific key-fob (and any spare) and close properly. Some fobs are bulky; check dimensions. GoDark Bags
- Durability & materials: Metal shells (hard boxes) tend to be more robust; fabric bags require good material. Some bags degrade over time. Auto Express+1
- Convenience & usage: If the box is too bulky, you might skip using it—which defeats the purpose. Choose a form you’ll actually use every day.
- Budget vs. value: The ultra-budget options may work in a pinch, but consider if cost savings trade off effectiveness. Article suggests “not all Faraday bags are created equal.” Howden Insurance
My recommendation based on use case
- If you really want maximum protection (premium car, high risk area) → pick something like the GoDark Vault (metal, top quality).
- If you want solid protection at moderate cost → mid-price safe box or reputable bag (e.g., Mission Darkness, signal-blocking safe box).
- If you’re just experimenting or have low risk setting, a budget pouch or two-pack may suffice—but be sure you test it.
- If aesthetics matter (nice home entryway box) → something like wood finish JXE/JXO or stylish PU leather briidea.
- If you have multiple keys/spares, go for a 2-pack or box with capacity.
🔍 My Top Picks & Why
- Best overall (premium): GoDark Vault — highest build, full features, peace of mind.
- Best value moderate: Signal Blocking Faraday Safe Box (~$25) — good cost-to-quality ratio.
- Best bag format: Mission Darkness Faraday Bag — flexible for more than just keys, good brand.
- Best budget: Carevas 2-Pack — for holding spares or testing the approach.
- Best design/entryway box: JXE/JXO or briidea — for form + function.
- Worst (but acceptable) budget option: Car Key Faraday Bags (~$8) — only if you test and accept limitations.
🧪 Testing & Usage Tips
- After placing your key/fob in the box/pouch, test it by approaching your car until it would normally auto-unlock. If it still unlocks, the shielding isn’t working. carwow.co.uk+1
- Keep the faraday box for keys in a consistent location (entryway, drawer) so you don’t forget to use it.
- Use it for all key-fobs (primary + spares), especially if they are stored near exterior walls/windows.
- Remove the key from the box before walking to your car if you expect auto-unlock. Don’t keep it in the box while trying to use features.
- Periodically check the box/pouch for wear, gaps, damaged seams. Bags degrade; boxes may warp.
- If you travel or park in unfamiliar/less safe places, use the box as part of your security routine.
- Combine with other security measures: physical locks (steering wheel lock), disable remote start if possible, park in well-lit areas. AP News
Key Takeaways
- A Faraday box for keys is a practical preventive measure against keyless/fob-relay car theft by blocking the wireless signal from your key.
- They work by applying the Faraday cage principle: conductive material shields or redirects electromagnetic signals.
- For best results: choose a quality box, test it, use it consistently, and combine with other vehicle security practices.
- They are not a silver bullet—physical theft, other hacking methods, and human error (forgetting to use it) remain risks.
- Given the modest cost compared to the potential loss of a vehicle, many security experts advise key owners to adopt this measure.
References
- “What is a Faraday bag and do you need one?” – Carwow. carwow.co.uk
- “How to Prevent Key Hacks and Relay Attacks” – Compustar blog. Compustar
- “Will A Faraday Cage Stop Keyless Car Theft?” – YouTube video. YouTube
- “Relay Attack Risks and Prevention” – Identity Management Institute. Identity Management Institute®
- “Best Faraday bag car key signal blockers 2025” – Auto Express. Auto Express
- “Car Key Signal Blocker Faraday Box – Do They Work?” – YouTube review. YouTube
- Wikipedia: Faraday cage. Wikipedia
- “Preventing keyless car theft” – EyeQ Monitoring. eyeqmonitoring.com
- GoDark Vault specs (frequencies, aluminum thickness, closure). GoDark Bags
- Mission Darkness keyfob bag features and use. MOS Equipment
- SLNT key fob bag sizes and materials. SLNT®+1
- DefenderShield key fob bag overview. DefenderShield+1
- TICONN 2-pack listings/prices. Amazon+1
- briidea Faraday box descriptions.
- Burger Tuning Faraday safe box.
- Faraday Defense key fob dry bag.
- Koruma large Faraday box (Etsy).
- “Does it work?” test guidance. SLNT®
