Microsoft Optical Technology 1000 dpi provides responsive cursor control. Snap-in Transceiver Stows conveniently under mouse for portability. Power switch turns the mouse on and off for up to 8 months of battery life. Designed for Comfort Comfortable in left or right hand. Scroll Wheel For faster on-screen navigation. Power Switch Turns the mouse on and off. Longer Battery Life Up to 8 months of battery life. Easy-Access Hot Keys Quickly access Calculator, volume controls, mute, and play/pause. Windows Start Button Simply press to launch your Start menu. Longer Battery Life Up to 15 months of battery life.