Bosch GXS18V-11N25 CORE18V Compact Starter Kit features two batteries and a charger to deliver cutting-edge battery performance and charger flexibility. The CORE18V Compact Battery is the next-gen Lithium-ion battery to keep the power and runtime, while losing the weight. Engineered with 21700 cell technology, the GBA18V40 single-layer battery matches the power from the original two-layer 4.0 Ah battery with improved performance per cell. The Bosch GAL18V-40 4.0 A charger can completely charge a discharged CORE18V 4.0 Ah battery to 80% in 48 minutes and to a full charge in about an hour. This dual-stage charger charges the first 80% in fast charging mode and the remaining 20% in long-life mode, getting the user back to work quickly. It features charging indicator lights showing when the battery is fast charging, charging in long-life mode or finished charging. The battery provides exclusive CoolPack 2.0 technology to manage the heat of the higher power-density cells, and it provides better cooling than the previous 4.0 Ah double-layer versions. This new-gen CORE18V still features compatibility with Bosch 18V Lithium-ion tools and chargers.