Lightweight: Bosch 18 Volt Compact battery with 2.0 Ah and COOLPACK technology is lightweight, making it ideal for overhead applications. COOLPACK technology provides up to 100% more lifetime than a battery without COOLPACK. Due to the special, heat conductive housing, the cells are optimally protected against excessive heat. 18V Professional System: All Bosch Blue Li-ion tools and chargers in the same voltage class are 100% compatible. The battery voltage is 18 V, and the weight is 350 g.