Adesso iMouse M20 - Wireless Ergonomic RF Optical Mouse for Windows 8/7/Vista/XP Features: DPI Switch, Scroll Wheel, Auto Sleep Mode, On/Off Power Switch, Connect Button & (2) Internet Navigation Buttons (Forward & Back) Interface: 2.4 GHz Radio Frequency Wireless Technology Range: Up to 30ft (10m) Adjustable DPI: 3 Levels (500, 1000, 1500) Power: (2) AAA Batteries, included Indicator: Low Battery Hand Orientation: Right Hand Tracking Method: Optical Sensor