Thumbs Up EP-5S Black has a new ergonomic profile (hence the "EP" designation). This model is our 5th EP version, but and is intended for use on the X100 or X10 cameras. The thumb rest is angled at 15 degrees, and this shape helps distribute the pressure from your thumb more uniformly. This refinement allows you to hold your camera with less gripping pressure, yet with great comfort and stability. By reducing the gripping pressure, you will reduce camera shake, making hand held images with slower shutter speeds possible.