Win 1 of 5 Armourcards from Traveltalk

The answer to the question is: "About the same size as a credit card".

A little info about the product from the story:

New credit card and passport technology actually puts consumers at risk. Why is that?
Your tap and go credit cards and passports all work on technology called Radio Frequency Identification (RFID) and the nature of this technology means that data is transferred wirelessly over open airwaves.

The flaw with this technology is that anyone, and I mean anyone, can buy a reader off eBay for under $60 and anyone can download free software online that can turn a tablet or laptop into a skimming device when teamed with that reader.

And that’s not the worst of it. You can now download free Smartphone apps that read, or skim, credit cards – some go as far as to skim the credit card, showing a picture of the complete card on the hacker’s Smartphone screen. So today, anyone can intercept your tap-and-go signal and read it by simply standing close to you.

So how do people protect themselves?
We’ve produced what we call a ‘Second Generation Protection Product’. We deem ‘First Generation Products’ as RFID blocking wallets and travel pouches, for example. These ‘passive’ devices can often still be penetrated if a criminal boosts the power on their reader.

My business partner and I weren’t happy with our data being out there in this open, wireless world and we realised that a technology-based crime needed a technology-based solution.

So we created Armourcard, which is about the same size as a credit card and fits into your wallet. When someone tries to interrogate those cards it will instantly power up and jam the frequency – the communication link between the reader and your card – so nothing can be transmitted even if the criminal tries to boost up the reader signal. It protects everything within 50mm either side. If you place the Armourcard between a stack of around four passports, it will protect them all too.