I was in a shop in central London a couple of weeks ago looking at carry on luggage for a business trip when I stumbled upon the SECRID wallet.
Now the SECRID wallet is sold in two formats:
1. The card Protector on it's own
2. The card protector attached to a Leather case/wallet.
Whilst the card protector with the leather case is not exactly slim, the card protector alone is extremely slim and minimal.
The card protector retails for around £25 making it an extremely well priced priced card holder.
It holds up to 6 credit cards, protects your wallets from RFID skimming and has a unique mechanism which simultaneously ejects the cards and fans them out for easy selection.
For more information, below is a video of the card protector in action.