18v, compact, lithium-ion, 2.0ah battery, integrated led battery charge level indicator allows user to monitor battery charge, provides up to 50 percent more run time per charge, reaches full charge in 25 minutes or less, compatible only with star protection tools, indicated by the star symbol & or yellow battery receiver under tool, battery 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 battery, battery resists self-discharge & remains ready for use even after long periods of storage.