Kensington Expert Mouse - Wired Ergonomic TrackBall Mouse for PC, Mac and Windows with Scroll Ring, Ambidextrous Design and Optical Tracking - Grey (64325) : Amazon.co.uk: Computers & Accessories
Seenda Trackball Mouse Wireless, Ergonomic Thumb Control Rollerball Mouse, 2.4G USB+ Dual Bluetooth Connection, Rechargeable Mouse for Windows Mac Android iPad Computer Laptop PC Tablet: Amazon.co.uk: Computers & Accessories