This is the leather chain wallet here from Isaac Reina shown here in a superbly vibrant red colourway.
The style is a single zip wallet and attached to it is a sturdy leather strap which can be hooked through a belt loop and then placed in your pocket so you have less chance of it going missing or falling out.
A perfect size for cards, notes and coins and also available in a punchy yellow colourway this is a really desirable piece from a very interesting, exclusive and talented young designer.