Bosch 18V 5.0Ah Coolpack Lithium Ion Batteries. These batteries are fully compatible with existing Bosch 18V power tools and chargers that support 4.0Ah and 3.0Ah Coolpack batteries. They feature electronic coding, high power contacts with silver coating, a capacity indicator with 3 LEDs, and a red Cool Pack housing constructed of heat conductive material. Built-in temperature sensors and a large ergonomic release button enhance ease of use. Bosch's efficient cooling technology prevents heat damage, extending run-time by up to 65% and battery lifetime by up to 100%. The 5.0Ah cells offer greater power density and efficiency with less electrical resistance compared to 3.0Ah cells. This package includes two 5.0Ah Coolpack batteries.