If your car has keyless entry, a Faraday pouch provides an extra level of security against potential theft.
Here, we explain how they work, if they’re legal, and what you can use instead. And we also share nine of the best Faraday pouches on the market today.
A quick reminder: What is keyless entry?
Keyless entry is convenient and common in modern cars. To work, your car key continually emits a Radio Frequency Identification (RFID) signal. This signal passes through your pocket or bag and, when you’re within range, is received by your car’s sensor. When the right signal is received by your car, the locks are opened, and voila — you gain entry without needing to put the key into the lock.
However, there are downsides. The RFID signal from your car key doesn’t have an on/off switch, meaning it’s constantly putting out its signal.
A Faraday pouch contains your car key’s signal, making it difficult, if not impossible, for thieves to pick it up, amplify it or clone it to gain entry to your car.
Read more: Car Immobiliser: Your Definite Guide
How do Faraday pouches work?
The Faraday cage was invented by the scientist Michael Faraday. He found that creating a complete enclosure of conductive metal distributed electromagnetic currents around the outside of that enclosure, keeping the inside free of charge.
There are a few stipulations for creating a robust Faraday cage or pouch. The shield created needs to be thick enough to absorb and distribute currents directed at it. If the shield is made of mesh, the gaps need to be smaller than the wavelength of the frequency being aimed at it.
Most Faraday pouches or boxes are made of lightweight conductive metal mesh woven tightly enough to block electromagnetic waves from passing through. That means your RFID signals are contained within the pouch. This stops any attempts to pick up that signal and clone or amplify it.
Faraday pouches can also be used to protect your phone from hacking, guard your credit cards and even block attempts to clone a digital passport. Larger Faraday bags can be used for protecting laptops and other bulkier electronic devices. By containing RFID and other electromagnetic signals, you’re keeping your information away from prying thieves.
Are Faraday bags illegal?
Faraday bags, pouches, and boxes aren’t illegal. Instead, they protect you from illegal activities, such as thieves trying to steal your data or vehicle, or gain access to a property using your personal information.
Does a Faraday pouch drain batteries?
A Faraday pouch won’t drain your batteries. It simply contains the electromagnetic and radio waves of your electronics and keyless entry keys within it. It also stops external electromagnetic interferences from reaching the items inside.
Your keyless entry keys have a small battery inside that typically lasts around 2 years. Popping your keys, phone, or other electrical devices into a Faraday pouch won’t drain the battery. If anything, it may preserve the battery life because it stops your keys from communicating with your car.
What can I use instead of a Faraday pouch?
Some heavy-duty tin foils can be used to make a Faraday pouch. A thick tin box can be used as a Faraday box for car keys too. These work in a similar way — creating an impermeable case for your electronics and RFID-emitting keys.
The biggest difficulty with using a makeshift Faraday bag from tin foil is re-use. Wrapping and unwrapping keys or other objects is bound to wear the foil. As soon as a small hole appears in your foil, your security is compromised.
If you are using a metal tin, it’s best to test the thickness. You can do this by enclosing your keys in the tin and holding them close to your car. If your car unlocks, the metal is either too thin or has a small hole in it somewhere.
Even Faraday pouches or a Faraday box for car keys can be compromised if they’re torn, not closed properly, or just not thick enough to contain the signal you’re trying to hide. A Faraday pouch, whether purchased or homemade with foil, only works when it fully encloses the item inside.
What are the best Faraday pouches?
Not all Faraday bags and pouches are created equal. Low-quality materials and poor construction can result in a bag that soon loses its effectiveness, or never worked to begin with.
The best Faraday pouches have been lab tested and come with dB ratings. The higher the dB rating, the greater the level of effectiveness. You can, of course, test your own Faraday box or pouch by enclosing keys in it and holding it within range of your vehicle. If the vehicle stays locked, the box is secure
Expect to pay anywhere between £5 to £20 for a Faraday pouch big enough to securely store your car keys. Additional features such as pockets for credit cards, keyrings, or chains for attaching to other sets of keys or a bag are also worth looking out for.
To help you choose the right Faraday pouch to keep your valuables and information safe, we’ve listed our top nine choices below.
1. Mission Darkness Faraday bag for key fobs
The Mission Darkness™ Keyfob Shield is a high-quality Faraday bag made with durable, water-resistant materials. It has three layers of high-shielding fabric and is large enough for two key fobs or an average set of keys with keyrings. This high-grade Faraday pouch comes as a set of two and is used for vehicle security, executive travel, data privacy, and personal security.
2. Defender signal blocker
This Faraday puch for key fobs comes as a set of two. It’s large enough for a set of average keys or a mobile phone. Made from industry-leading RPF material, it blocks attempts to jack car key RFID signals and mobile phone transmissions. Calls, SMS, and notifications are blocked for phones placed securely in the Defender Signal Blocker.
3. Disklok RFID Car Key Pouch
Makers of steering wheel locks and other car security items, Disklok’s Faraday pouches for car keys, and similar items are a sound choice. Measuring 14cm x 9.5cm, it’s just the right size for a small set of keys and several credit cards. It comes with a small carabina that’s perfect for attaching to the inside of your bag or a belt loop on trousers.
4. Specialist Automotive Solutions Faraday box for car keys
Perfect for storing keys at home, SAS’s Faraday box for car keys is large enough to securely store several sets of car keys, a mobile phone, and credit cards too. The box also comes with two small pouches for storing keys when you’re out and about.
5. Disklabs Key Shield
Disklabs have a wide range of Faraday bags, small enough for keys and large enough for laptops. The KS1 Faraday bag is designed for car key fobs. Measuring 11.5cm x 11.5cm it’s small enough to slip into a pocket or shoulder bag. It’s made in the UK and has Secured by Design approval, the official police recognition initiative for security products.
6. Halford’s Anti-theft Car Key Signal Bocker
Large enough for a small set of car keys and made from a satisfyingly durable material, Halford’s anti-theft car key signal blocker pouch comes in black, red, and blue. Small enough to fit in a pocket or bag but large enough for keys and a few credit cards, this is an ideal choice for drivers wishing to stop car thieves.
7. Olixar RFID Car Key Signal Blocking Pouch
Olixar’s anti-theft pouch in rose gold is a small yet perfectly formed Faraday pouch that’s ideal for safely tucking a single set of keys into your purse. The pouch has twin pockets that store credit cards safely along with keys. Made from faux leather with a carbon fibre edge, it also has a short chain and key ring.
8. Krutz Faraday Pouch
Made from vinyl faux leather, this sturdy key fob pouch is secured with two press studs instead of velcro. A short chain with a keyring makes it easy to attach to other keys and store in a bag or pocket. The Krutz Faraday pouch for car keys comes as a two-pack, making it simple to keep spare keys secure too.
9. Argos Streetwize Car Key Signal Blocking Pouch
This handy double pack of signal-blocking Faraday pouches from Streetwize at Argos provides vehicle security and total peace of mind. Made with a double layer of high-quality 600D Oxford cloth. The pouch works well at blocking any signals from smart devices, debit or credit cards, and keyless fobs.
For more ideas for keeping your keyless car safe, read: Keyless car theft: how to avoid becoming a victim.