Nice video on youtube :-)

Thumbs Up CSEP-2 is a new product – for use with the Leica X1 and Fuji X-Pro1 camera.

Thumbs Up CSEP-2 has a comfortable ergonomic profile (hence the “EP” designation). The thumb rest is angled at 22 degrees, and the special shape distributes the pressure from your thumb uniformly. This refinement allows you to hold your camera in a extremely stable manner, yet with great comfort.