HP 2.4 GHz Wireless Optical Mobile Mouse (Gray) Compact, ergonomically comfortable wireless mouse in gray with blue LED and contoured edges--great for use at home and on the road Adjustable sensitivity from 1250 to 1750 cpi for maximum workability on a variety of surfaces Four buttons: two primary buttons, clickable scroll wheel and a document flip button Connects to PCs via USB micro receiver (2.4 GHz) that's so small you can leave it plugged into your notebook Compatible with Microsoft Windows 2000, XP, Vista, and 7 operating systems