Amazon.com: Kensington Orbit Mouse - Wired Ergonomic TrackBall Mouse for PC, Mac and Windows with Scroll Ring, Ambidextrous Design and Optical Tracking - Blue (K72337EU) : Electronics
User manual Kensington Orbit Trackball (English - 31 pages)
Kensington Orbit K72337 Black Wired Optical Trackball Mice - Newegg.com