It works when you have nothing else to use

The shape won't fit anyone's hand

optical

shape is horrid, extremely uncomfortable

It works as an optical mouse should but

causes sever wrist pain

Flows great, just like an optical mouse should.

The design of the body is so narrow, no one can comfortably put there hand on the mouse without fatique. I first thought that maybe because i'm a 43 year old male but I had one of the ladies with smaller hands try it and she does not like it either.