Orbit trackball with scroll ring features optical technology that delivers precise cursor control with the touch of a finger. The two-button design provides an interface that's familiar to mouse users. Scroll ring allows fast, easy click-free scrolling of web pages and documents. Compact design uses far less desk space than a mouse. Ambidextrous trackball is designed for left-handed or right-handed users. Trackball offers USB connectivity and is compatible with Windows 7, Windows XP, Windows Vista, and Mac OS X.