Best signal-blocking Faraday bags for car keys in 2021
Specially lined Faraday wallets can help prevent your car from being stolen
If you buy a new car that comes with a smart car key, you’ll be able to enter and/or start your car without taking the key out of your pocket. Although this makes life easier, the technology has also created a new way for criminals to steal cars, so you may want to consider buying a Faraday bag to protect against this.
A smart key uses a unique frequency to communicate with the car, and tech-savvy thieves can use a relay attack device to replicate that frequency. Once copied, the thieves simply place the relay device near your car to emulate the presence of the key, open the door and drive off, with no smashed glass, car alarms or complex ignition systems to worry about.
A Faraday bag eliminates this concern. Lined with a layer of metal, it essentially isolates your key and its frequency so that it isn’t transmitted or copied. A Faraday bag also works with smartphones and credit cards.
There are a number of Faraday bags on the market and we’ve tested eight of them to find out which is the best one to buy.
How the Faraday bags were tested
In the first test we tried to open the car door with the car’s key in the Faraday bag next to the drivers door handle. Next we pressed buttons on the key fob within the bag. Finally, with the key still bagged up in the cabin, we pressed the engine start button.
We also assessed the build quality, cost and usability of the bags. An app was used to check the phone, Bluetooth and Wi-Fi signal-blocking capabilities.
The results were very close because all the products worked as the manufacturers stated. With this in mind, we turned to the quality, practicality and value for money offered by each of the products.. The best signal blocker was the Defender, a Faraday bag that’s big enough to accommodate other items too. Both the Disklabs KS1 and the Ecence weren’t far behind.
Defender Signal Blocker
Price: Around £5
Size (cm): 18.5 x 11.5
Our winner successfully blocked all signals and had excellent build quality. Surprisingly, it’s the cheapest to buy too. It’s the second largest bag out of the ones tested, easily handling larger phones, but it could be a bit excessive if you only have a small set of keys. We were happy to accept its size given the benefits the Defender gives you for the price.
Disklabs Key Shield Faraday Bag KS1
Price: Around £28
Size (cm): 12 x 10
The Disklabs bag instantly inspired confidence, as it was the only one here given the ‘Secured by Design’ accreditation from the police. The build quality was among the best here and the effectiveness of the signal blocking worked even with the flap still open. It would fit most keys nicely. It’s a pricey choice, but it feels like a sound investment.
Ecence RFID Radiation Protection Bag
Price: Around £9
Size (cm): 12.5 x 8
Designed for key use only, the Ecence bag is exactly the same as the Halfords and B-G, aside from the fact it’s cheaper, hence why we rated this one higher. It performed signal blocking well, the material itself thick and reassuring. The only quibble we had was the lack of stitching quality, especially at the bottom of the bag and whether this had the potential to wear with use.
B-G RFID Keyless Entry Car Key Fob Signal Blocking Faraday Bag MIS1003
Price: Around £3
Size (cm): 12.5 x 8
A great feature of the B-G is that you can choose two sizes; a smaller one for just keys or a larger one for items like phones. The build and results were almost identical to the Ecence bag, just for slightly more money. The B-G had a chrome ring on the back, perhaps for hanging the bag on your key hook indoors. There was also a keyring on the top.
Halfords Anti RFID Theft Wallet
Size (cm): 12.5 x 8
The Halfords bag lost out to its cousin the Ecence on price. As with the Ecence and B-G though, build and signal blocking were up to standard, aside from perhaps the stitching in the bottom of the bag. Different to its relations, the Halfords bag specifically mentions it can be used with credit cards. You could easily fit a few in there too.
TVL Anti Scan Wallet
Price: Around £24
Size (cm): 14 x 9.5
TVL is the second most expensive here, but as with the Disklabs KS1 and PS1 bag, you could see the quality would mean it would last even with daily use. The lining worked well for blocking the key signal and also worked with phones when the flap was closed. The vinyl coating adds to the sturdy feel, but doesn’t bode well for folding it away into a pocket.
Disklabs Phone Shield Faraday Bag PS1
Price: Around £31
Size (cm): 11.5 x 19
The most expensive but also the biggest, measuring up larger than the Defender. The PS1 also has the same police recognition as its smaller sibling, the KS1. It could fit phones and keys together inside, with only a slight struggle when including larger key sets. Despite the price, the size makes it worth the extra cost, although it would be a bit too cumbersome for easy storage in a pocket or bag.
TrackingUK Faraday Key Signal Blocking Wallet
Price: Around £12
Size (cm): 14.3 x 10
For subtlety, the TrackingUK bag was the best. It was by far the lightest of the set and easy to fold away and store. Blocking phone signals was a little more hit and miss but it worked perfectly well on the keys. The price for the quality of material and stitching seemed a bit high though, particularly given it didn’t seem as durable as some other options here.
Looking for other ways to protect your car from keyless go theft? Read our guide on the best steering locks to stop theives in their tracks.