Bellroy Card Sleeve.

A tiny sleeve for use as a wallet or business card holder. The Card Sleeve is the slimmest style in the Bellroy arsenal. It can be used as a business card holder, or even as a full-time wallet for those who have a black belt in slimming their pocket contents. The main section features a pull tab for easy storage of cards and money, while the outside pockets can be used for quick-access items.