Adesso iMouse E10 - Vertical Ergonomic Optical 6-Button 2.4 GHz RF Wireless Mouse - Right Hand Orientation 2.4 GHz Radio Frequency Wireless Technology Ergonomic Vertical Design Back & Forward Button for Conveniency 2.4 GHz Radio Frequency Wireless Technology and tracking method is optical sensor Ergonomic Vertical Design. The vertical design provides better support for your forearm minimizing wrist pain that can come from twisting. Back & Forward Button for Convenience. Two Internet navigational buttons, back and forward, are conveniently located on the left side of mouse to provide you with Internet browser control with minimal hand movement. DPI Switch Button. Quickly and easily adjust DPI resolution (1000/1500/2000 DPI) for a faster response with the convenient DPI Switch located right beside your thumb. Battery-Saving. Use the battery-saving on/off power switch on mouse base to extend battery life and reduce the need to change batteries. 2 AAA Batteries Included Windows 8/7/Vista/XP/2000 Mac OS X and above