18V Li-Ion 4Ah Battery

18V, Lithium-Ion Battery, Bosch Exclusive Cool-Pack 2.0 Technology Provides Up To 135% More Battery Life Than BatteriesWithout, 1.8 LB Provides Performance Comparable To Batteries That Are Up To 35% Larger, Features Backward & Forward Compatibility With All Bosch 18V Tools & Chargers, Charges To 80% In Only 41 Minutes & 100% In Only 55 Minutes Using The Optional Bosch BC1880 18V Fast Charger, Works In Cold Weather Conditions Down To -4 Degrees.