Seamlessly switch between 3 devices. Logitech Advanced Optical Tracking and boosted efficiency - 24 months of power on a single AA battery. 3G Core scroll wheel with 8 buttons. Tilt wheel with middle click. Bluetooth Smart connection. 2.4 GHz wireless connection with 10 m of wireless range. 1 "AA" battery (included). 1-year limited warranty. Small. Black.