Best Faraday bag car key signal blockers 2026
We reveal the best way to counter the threat of car thieves using relay equipment
Most of us will know someone who has had their car stolen in the past few years. Virtually all vehicles have standard-fit electronic security systems, and while this has thwarted thieves who use screwdrivers and crowbars, it gives an opportunity to more sophisticated criminals who can hack the technology.
The most common way is to use relay equipment, which captures and then boosts the signals from key fobs, even if they are safely inside your home. To protect your car, the police and other experts suggest you keep the keys in a pouch that blocks the signals. These are known as Faraday bags after the scientist who discovered the electronic blocking principle nearly 200 years ago.
They can cost just a few pounds and vary in size from ones that fit in a pocket to others that can take a collection of keys. Which is the best blocker?
How we tested
The first test was to try to open three ‘keyless’ cars using fobs stored in the pouches. Foil pouch liners can degrade quickly, so next we simulated 18 months of being handled twice a day by tumbling them 1,200 times with keys inside.
We then tried again to open and start the cars, placing the pouches next to the sensors. We gave features such as loops and chains extra points and judged value, noting that some come in a twin pack.
Hilka Pro-Craft Faraday Car Key Signal Blocker
- Price: around £7.99 (twin pack)
- Size: 14 x 9cm
- Rating: 5.0 stars
- Contact: screwfix.com
Used - available now
2013 Mercedes
SLK
53,440 milesAutomaticDiesel2.1L
Cash £8,852
2024 Renault
Austral
17,457 milesAutomaticPetrol1.2L
Cash £22,149
2020 BMW
X1
33,096 milesAutomaticPetrol1.5L
Cash £18,249
2024 Audi
A3 Sportback
14,368 milesAutomaticPetrol1.5L
Cash £25,799It is not the most feature-laden pouch in this test, but it was hard to find fault with the way the no-nonsense Hilka performed. Before and after the endurance trial it blocked all the signals, and the larger Velcro strip on the top flap meant it fastened equally well with bulky or smaller key fobs. With two pouches in the £7.99 pack, it is decent value too. Our only criticism is that the Hilka has a separate unprotected pocket at the front. This is unnecessary and it’s easy to slip a key in there by mistake.
Temu Faraday Car Key Pouches
- Price: around £5.68 (2 pack)
- Size: 14.5 x 9.5cm
- Rating: 4.5 stars
- Contact: temu.com
Despite costing just £2.84 each, the Temu pouches have a smart carbon-look finish and chunky chrome clips and rings. Each one has different-coloured stitching too, so you can tell your keys apart from your partner’s at a glance.
As in the winning Hilka, a wide Velcro flap ensures the contents are covered even when the pouch is stuffed with a key. This pouch only lost out on the top spot because it was possible to get a very faint signal if you overfilled the pocket and fastened it clumsily.
Disklabs KS1 Faraday Bag Signal Blocker
- Price: around £24.99
- Size: 12 x 10cm
- Rating: 4.0 stars
- Contact: fonefunshop.com
If money were no object, we’d choose the Disklabs KS1, because it has a high-quality look and feel. The chunky canvas pouch is compact but appears to be shaped perfectly for keyfobs.
Its Velcro fastener seems much stronger than any rival here too, while an extra tab makes it easy to open up and remove your keys. There’s a fabric loop to attach a keyring or chain too. Once our keys were inside, the signals were totally blocked. But the price is too high for a win.
Stoplock Anti Theft RFID Protection Pouch
- Price: around £8.02
- Size: 19 x 10cm
- Rating: 3.5 stars
- Contact: amazon.co.uk
The biggest pouch here is just large enough to fit a normal smartphone, although it’s a squeeze and you wouldn’t be able to fit your keys in too. Oddly, it doesn’t seem to work with bulky key fobs particularly well either, because the bands of Velcro are too narrow to fasten effectively if there is any bulge in the pouch. However, even with the flap open, it blocked the key’s signal effectively.
Simply RFID Wallet
- Price: around £5.99 (twin pack)
- Size: 13 x 9cm
- Rating: 3.5 stars
- Contact: thompsonsltd.co.uk
Simply’s pouches look great value at under £6 for a twin pack and it breezed through the tests before and after the endurance trial. It did leak signals slightly when the pouch was very full, though, because it is difficult to get the flap shut cleanly when the wallet isn’t perfectly flat. There are no chains or loops for keys either. Plus, if you have a larger fob or a bigger bunch of keys, you’d be better off with one of the rivals.
Halfords Car Key Signal Blocker
- Price: around £4
- Size: 13 x 9cm
- Rating: 3.5 stars
- Contact: halfords.com
We had a sense of déjà vu when testing the Halfords Blocker because its looks and performance are identical in every way to the Simply product, so we assume they come from the same maker. The one difference is that Halfords charges £4 for one, and Simply asks £5.99 for two. If you don’t need a pair, go halves with a friend on the Simplys and you’ll each save a quid.
AA Anti-Theft RFID Pouchspec
- Price: around £11.95
- Size: 12.5 x 11cm
- Rating: 2.5 stars
- Contact: ebay.co.uk
Although it passed all of our tests, we found it hard to get on with the AA pouch. It is almost square and despite being larger than some, it’s awkward to put bigger keys in. The fastener is a magnet rather than Velcro too, and it kept popping open.
Verdict
The Hilka Pro-Craft Faraday Car Key Signal Blocker has no frills, but it works well and is good value. Temu’s pouches cost even less and add a few nice features; only a slight chink in the armour of protection kept them off top spot. Third place goes to the Disklabs KS1, which is great, but far too expensive.
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