What is the difference between the Nano Boy and the Nano Boy Pocket?

The Nano Boy Pocket has a larger coin compartment made of leather. The Nano Boy has no leather coin compartment. But you can also store coins in the elastic coin pocket of the Nano Boy. Of course less than in the Nano Boy Pocket and also not as comfortable to reach, but the Nano Boy is much thinner than the Nano Boy Pocket, especially if you don't have any coins.