All-day comfort and scrolling come together in the Orbit Trackball with Scroll Ring. Award-winning Scroll Ring lets you scan up and down pages with ease. Medium 40 mm ball is designed as a perfect sphere to provide exceptional precision. KensingtonWorks™ software lets you customize the two buttons, adjust cursor and scrolling speed. Optical tracking technology for superior cursor control and accuracy. Detachable wrist rest supports hand and wrist for ergonomic comfort. Ambidextrous design works equally well for both right-handed and left-handed users. Plug & Play installation via wired USB connection. PC and Mac® compatible.