Logitech Cordless Trackman Optical Trackball mouseAn input device that looks like an upside-down mouse. The onscreen pointer is moved by the trackball with a thumb or finger.

A trackball requires less arm and wrist motion that a regular mouse takes and therefore is often less stressful for the user to use, helping to prevent RSI. The picture of the Logitech cordless trackball mouse is an example of a trackball mouse that uses the thumb for movement.

Related pages

Also see: Mouse, Mouse terms, Pointing device