BlueTrack Technology allows tracking on many surfaces Advanced optical technology allows use on more surfaces than either an optical or laser mouse. With Microsoft BlueTrack Technology(TM), the mouse can track on surfaces like granite countertops, carpet or even rough wood. (Does not work on clear glass or mirrored surfaces.) 2.4GHz wireless provides range up to 15ft.. Compact nano transceiver can stay connected to your notebook computer when you travel. Battery typically provides up to 8 months of use. Power status indicator lets you know when a replacement is needed.