The Bosch CORE18V 4 Ah Advanced Power Battery is a compact battery delivering power in a lightweight solution. It allows you to get the power and lose the weight. The GBA18V40 delivers high power in a compact size for standard to medium duty applications, such as drilling into concrete, metal and wood, metal grinding, cutting and even light duty chipping. It delivers 2x the runtime and 60% more power compared to BAT612 18V 2 Ah battery. The GBA18V40 is designed with high-power lithium-ion cells, featuring a single layer of enhanced 21700 cells for greater battery efficiency.