The Adesso Desktop Optical Trackball Mouse
is designed to fit the hand's natural position for maximum comfort. It has a scrolling wheel and a large detachable ball to make operating the mouse easier, and prevents repetitive motion injury. Ideal for family members who often work at a computer. Its 800 DPI resolution provides it with superior accuracy. Compatible with Windows 7/Vista/XP/2000 and Mac OS X or OS 9.