The Bosch BAT612-2PK 18V Lithium-Ion 2.0 Ah SlimPack Battery 2-Pack features two batteries that each provide outstanding runtime with a compact size. The battery weighs only 0.75 lbs., which is ideal for professionals who do a great deal of work overhead. It features CoolPack housing, which channels naturally occurring heat from within the inner core of the battery and dissipates it. This results in 100 percent more recharge life versus a battery without CoolPack. Built with low-resistance Li-ion cells, the battery is efficient and delivers significant power. As part of the Flexible Power System, the battery is compatible with all Bosch 18V Lithium-Ion tools and chargers. It features single-cell monitoring for longer runtime and works with electronic monitoring systems to prevent tool and battery overheating or overloading.