Microsoft Wireless Optical Desktop for Bluetooth Uses Bluetooth technology that allows you to get up to 30 feet away from your computer Connects up to 7 Bluetooth compatible devices to your PC Ergonomic engineering delivers the ultimate in comfort and support Microsoft Optical Technology provides a smooth, accurate experience&#8211; with no mouse ball to stick and no moving parts to wear out Compatible with Windows XP with Service Pack 1 and the Windows XP update for Bluetooth