Adesso 2.4Ghz Wireless Programmable Ambidextrous Ergonomic Trackball Mouse, with, Black, iMouse T40

Ergonomic contour design - Minimizes pain and discomfort in forearm muscles from twisting, which can cause carpal tunnel syndrome. Built-in 1.5” large trackball with optical sensor - accurately and precisely tracks with less muscle movement for maximum comfort. East to install programmable driver - friendly user interface that lets you change button assignments, DPI sensitivity, scrolling speed. Removable trackball - Can Be easily removed by pushing the trackball from underneath the mouse. Adjustable DPI switch - adjustable cursor moving speed from 400-4, 800 DPI.