The DEWALT 4.0Ah XR Li-Ion battery packLED State of Charge Indicator helps manage pack chargingLightweight design provides the user with upgraded 5Ah Power without increasing the size or weight over the 18V 3Ah battery packNo memory effect and virtually no self-discharge for maximum productivity & less downtimeCompatible with all DEWALT XR Li-Ion 18V ToolsProtection against overheat, overload and deep discharge conditions increases battery lifeExcellent electrical characteristicsNo memory effect