Adesso iMouse S20 - Wireless Mini Ergo Mouse for Windows 8/7/Vista/XP Tracking Method: Optical Sensor Interface: 2.4 GHz Radio Frequency Wireless Technology Adjustable DPI: 3 Levels (500, 1000, 1500) Features: DPI Switch, Scroll Wheel, Auto Sleep Mode, On/Off Power Switch, Connect Button & (2) Internet Navigation Buttons (Forward & Back) Indicator: Low Battery Hand Orientation: Right Hand Power: (2) AAA Batteries Range: Up to 30ft (10m)