HP 27MHz Wireless Optical Mouse - Silver Slim mini-receiver is so small you can store it inside the mouse Wireless freedom with 27MHz wireless technology Optical sensor with adjustable sensitivity (1250 CPI default, 1750 CPI max) works on many surfaces Rubber sides and symmetric design provide comfortable and secure grip for left or right hand use Compatible across all notebook and desktop platforms; System Requirements: Available USB port; Microsoft Windows /XP/Vista/7