Kensington Expert Mouse - Wired Ergonomic TrackBall Mouse for PC, Mac and Windows with Scroll Ring, Ambidextrous Design and Optical Tracking - Grey (64325)

KensingtonWorks Customization - Free downloadable software provides an even more personalized experience, giving you the ability to assign a wide variety of program functions to each of the 4 buttons, as well as controlling the pointer speed and scrolling speed DiamondEye Optical Tracking - Movement detection technology provides smooth, precise cursor control so you can get where you want on the screen quickly with less hand movement, improving productivity and efficiency Scroll Ring and Large Ball - Spin the dial to move up and down web pages or documents with complete ease while the grey ball has been specially designed with an absolute spherical, hard surface for precise tracking and control Ambidextrous Design - Works equally well for both right-handed and left-handed users to get the most out of their trackball Detachable Wrist Rest - Soft cushioning cradles the hand and wrist in ergonomic comfort for pain-free productivity during extended periods of activity on the computer Reliable wired USB connection - Wired 180 cm USB cable provides reliability and avoids need for batteries PC and Mac compatible - Mac running OS X or later with an available USB Port. Internet connections or CD ROM drives to install the software. Compatible with Windows 7, Windows XP, Windows Vi