Bosch, 18 Volt, CORE18V Starter Kit. Includes (1) CORE18V 4.0 Ah Compact Battery. Compact 18V battery provides next-gen power and runtime, while losing the weight, for tools used on the jobsite all day. Charging convenience allows users to charge a Bosch 18V 4.0 Ah battery to 80% in 48 minutes or to 100% in about an hour. High-power cells use enhanced 21700 cell technology, combined with advanced design, to produce higher power for a longer time. Cutting-edge cell design engineered to improve performance in tools used on the jobsite all day. Bosch-exclusive CoolPack 2.0 technology cooling the battery 15% faster than previous versions. Lightest high-power battery weighs only 1.15 lb., but provides performance comparable to much heavier batteries. Battery-status indicator provides indication if charger is in standard-charging mode, long-life mode or when charging is complete.