Comfortable ambidextrous trackball. Fingertip control with advanced optical sensor for exceptionally smooth tracking. Sleek ambidextrous design that fits either hand comfortably. Large trackball that improves control while reducing hand and wrist motion. Optical technology provides precision and accuracy, free of ball cleaning and unsurpassed reliability. Customizable buttons for easy access to key tasks. Windows 98, 2000, Me, XP, Vista certified and Mac OS 8.6 or later. USB and PS/2 connectivity. Manufacturer"s three-year warranty.