Kensington Orbit® Optical Trackball Mouse from Posturite
KENSINGTON ORBIT OPTICAL TRACKBALL MOUSE WINDOWS / MAC | eBay
Optical Trackball Mouse - Kensington - Adapt-IT
Kensington Expert Mouse - Wired Ergonomic TrackBall Mouse for PC, Mac and Windows with Scroll Ring, Ambidextrous Design and Optical Tracking - Grey ...
Kensington Orbit® Optical Trackball Mouse from Posturite