Contactless credit and debit cards are only just starting to take off in the USA, but with Apple Pay driving merchants to introduce contactless payment terminals, you are increasingly likely to find that RFID symbol on your bank cards when you receive replacements.

We’ve had contactless cards in Europe for a few years now, and they’re even more convenient than Apple Pay for low-value transactions. For anything up to £30 ($46), you don’t need to verify the transaction in any way: just tap your card against the terminal. You can even do this without taking the card out of your wallet. (Bank guarantees protect you against fraudulent transactions.)

Convenient, that is, unless you have more than one contactless card in your wallet. This can either lead to the wrong card being debited or, more usually, cause the transaction to fail. Truffol has come up with an iPhone 6 wallet case specifically designed to solve this problem … 

The slim leather case has two card slots. The outer one is designed to hold the contactless card you want to use by default. You can leave this card in the case and just touch the whole case against the payment terminal to make a purchase.

The inner slot is lined with what is essentially a very thin Faraday cage: a mesh wire embedded into the pocket to block radio signals. The inner card can’t be read by contactless terminals while it’s in the case. If you want to use that card, you instead remove it from the wallet.

I’ve tested it on several transactions, and it worked exactly as advertised. The card in the outer pocket was read when I held the back of the case to the terminal, the one in the inner pocket wasn’t.

The case would also be handy for anyone nervous about accidental payments or scams. While contactless cards only operate at very short range (in the order of six inches), there are RFID skimming systems out there. Potentially someone could read your card while standing close behind you in a queue or in an elevator, the kit hidden inside a bag. If you’re worried about that, just carry one contactless card and keep it in the inner pocket.

The iPhone snaps easily in and out of the plastic holder inside the case, but you will rarely need to. There’s a cut out for the power switch at the side, another for the camera at the rear.

The leather is cowhide, which is a hard leather with a relatively rough surface. My own tastes run more toward smooth, soft leathers, but this is a very personal thing–others prefer textured leather.

There’s also an earpiece cutout at the front. This solves one of the usual irritations with fully-enclosed cases: you have to completely open the case and fold the front flap around behind the phone to make a call. With this one, you can speak on the phone with the case closed (the microphone doesn’t need a cutout as it’s on the bottom of the phone, which is not enclosed).

The volume buttons and mute switch are covered, but the leather is thin enough to comfortably operate the volume controls through the spine of the case during a call. The mute switch is accessible with the case open.

With the case closed, it’s slimmer than most wallet cases.

The case is supplied with a clear screen protector, cleaning cloth and applicator. I’m not a fan of screen protectors so didn’t use this myself, but the complete package is great value at $29.99. In fact the whole thing looks more expensive than it is, from the elegant packaging to the metal embossed plate on the back of the case. If you have contactless cards already, and are concerned about either card-clash or skimming, this is a neat solution.