Mine has four buttons and is huge. The buttons can be assigned via software - finger, thumb, fist, whatever. Just to give you an idea of scale, the ball is the size of standard pool cue ball. Can switch up hands, fingers, etc.

Another idea a lot of folks don't know about is that you can get foot "mice" or simple USB pedals to "click". Check amazon for "usb foot mouse" "pedal", etc. A simple pedal clicker is about $15.

**