Adesso iMouseE1 - Vertical Ergonomic Illuminated Optical 6-Button USB Mouse - Right Hand Orientation Ergonomic vertical design Back and forward button for convenience DPI switch button Ice Blue illumination 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 (1000/1600 DPI) for a faster response with the convenient DPI Switch located right beside your thumb. Ice Blue Illumination: You'll be proud to show off your fashionable iMouse E1 with the "ice blue" illumination contrasting against the glossy black case. Optical Sensor Windows 8/7/Vista/XP/2000 Mac OS X and above