Kensington Orbit with Scroll Ring - trackball - USB - white, silver - K72500WW - Mice - CDW.com
Kensington Orbit Wireless Trackball with Scroll Ring Review - RTINGS.com
Kensington Orbit Mouse - Wired Ergonomic TrackBall Mouse for PC, Mac and Windows with Scroll Ring, Ambidextrous Design and Optical Tracking - Blue (K72337EU): Amazon.co.uk: Computers & Accessories