2 pack, 18v, lxt, lithium-ion, 3.0ah battery, integrated led battery charge level indicator allows user to monitor battery charge, reaches full charge in 30 minutes or less, compatible only with star protection tools, indicated by the star symbol and/or yellow battery receiver under the tool, delivers consistent power & run time in extreme temperatures, even in winter -4 degree fahrenheit/-20 degree celsius, equipped with star protection computer controls to protect against overloading, over discharging & over heating, impact resistant outer case & shock absorbing inner liner are engineered to protect the battery.