Perixx PERIPRO-506 Mouse with USB Trackball Mouse – 100 x 80 x 42 mm – 25 mm Glossy Trackball – Detachable Gel Palm Rest – Unroll Wheel : Amazon.co.uk: Computers & Accessories
perixx PERIMICE-517 Wired Ergonomic Trackball Mouse with 7 Buttons and 2 DPI Level, 11567 : Amazon.co.uk: Computers & Accessories