Microsoft Wireless Mobile mouse 3500, USB, ER, English, Pink, Retail BlueTrack Technology® Take advantage of BlueTrack Technology, which combines the power of optical with the precision of laser for remarkable tracking on virtually any surface. Plug-And-Go Nano Transceiver Leave the nano transceiver plugged in when you’re on the go, or stow it in the mouse. 8-Month Battery Life Use your mouse for up to eight months without having to change batteries. Battery status indicator tells you when battery power is low. On/Off Switch Conserve battery power by turning off your mouse when not in use. Comfortable in Either Hand Use your mouse with your left or right hand. Ambidextrous design makes it comfortable either way.