Specification: Operating range: 30 feet(MAX) Measurements(L*W*H): 4.9* 3.4*0.7 inch Weight(grams): 130g Operational current: 3. 7V Sleep current: +5db Max Charging current: <200mA Battery capacity: ≥ 300nAh Battery type: BL-5C Key numbers: 79 Applicable Systems: Windows 2000 Windows XP Windows Vista Windows CE Windows 7 Linux(Debian-3.1,Redhat-9.0 Ubuntu-8.10 Fedora7.0 tested)