Kensington Orbit® Optical Trackball Mouse from Posturite
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
Kensington Orbit Elite Mouse Trackball Corded USB Both Handed Black/Silver Ref 64327EU
Kensington (K72363WW) Wireless Trackball - Orbit Fusion Trackball Mouse with Scroll Ring; Ergonomic Computer Mouse for Right Handed Users, Ideal for Small Desk & Home Office,Black : Amazon.co.uk: Computers & Accessories
Kensington (K72363WW) Wireless Trackball - Orbit Fusion Trackball Mouse with Scroll Ring; Ergonomic Computer Mouse for Right Handed Users, Ideal for Small Desk & Home Office,Black : Amazon.co.uk: Computers & Accessories