The high-endurance 18 Volt XL battery with 4.0 Ah and Cool Pack technology -Up to 65% more run time compared to existing 3.0 Ah battery using high quality Li-Ion cells Bosch Cool Pack manages the temperature of the battery cells actively and reduces heat-up which is the main killer for every battery cell 18 V 4,0 Ah batteries have the same weight as existing Bosch 3.0 Ah batteries and are the lightest in the market LED Indicator for battery stage of charge Flexible Power System: 100% compatible to all Bosch Blue Li-Ion tools and chargers within same voltage class Smallest battery pack of its class in the market Technical Data -Battery Voltage-18.0V -Battery capacity-4.0Ah -Width-74mm