The cavity card is a 3d printed ‘drawer’ for your wallet. It’s printed with a material called Alumide. Alumide is a mixture of Nylon and Aluminium particles which offers enough rigidity and strength whilst still being light. The thin version of the Cavity card which I have is roughly as this as 4 card stacked together. The cavity card comes with a blank white card which you can use to stick to the back of the frame or you can choose to use another card, like for example a touch travel card. I decided to stick with the plain white backing for my testing.
In terms of what you can carry, I was able to fit a key and several coins plus a bit of room to spare. I found it a little awkward to put into some of my front pocket wallets though. It acts as more of a drawer rather than an enclosed case. So you need to be mindful of which way you’ve slipped the cavity card into your wallet or all of the contents will fall out. This can somewhat be remedied by putting another card over the top and slipping them in the same slot but at 5 cards thick it will start to get bulky.
Finally the pricing starts at around 17 euros (AUD$24, USD$18) which I feel is a little steep for something like this. However it is durable and well made so if you were to use it a lot it would probably work out to be quite affordable. Overall I feel this is an interesting and unique way to address loose coins for a slim wallet but I think I’ll stick with the coin pocket in my slim dungarees.