CST2545W(GL) (L-Trac Glow) USB Wired Ambidextrous High Performance Laser Ergonomic Backlit Trackball (Black) - Made in the USA Width 3.75" (9.5cm), Length 6.75" (17.1cm), Height 1.75" (5cm) Three LED's illuminate the ball a vibrant blue Ball Size: 2.25" LED lights will automatically Turn Off after 5 minutes of inactivity. Resolution: User selectable 400, 800, or 1600 counts per inch