Microsoft Wireless Mobile Mouse 3500 Limited Edition Studio Series - Linn Olofsdotter Blue Track Technology - Works on more surfaces than optical or laser technology Nano Transceiver - Leave it plugged in your notebook when you're on the go. The mouse has its own on/off switch Up to 8 months battery life - Power status indicator lets you know when your battery runs low Comfort - Designed by ergonomic experts for comfort in either hand On/Off Switch - Conserve battery power by turning off your mouse when not in use