4000mAh Replacement Battery for Milwaukee 18V REDLITHIUM XC Cordless Tools 48-11-1852 M18 48-11-1811 48-11-1815 48-11-1820 Fit for Milwaukee M18 Lithium Cordless Power Tools 48-11-1840 48-11-1850,Provides optimized performance and overload protection using total system communication between tool, battery and charger. Voltage: 18V, Capacity: 4.0Ah. Replace Milaukee M18 Lithium Battery Pack 48-11-1811, 48-11-1815, 48-11-1820 Individual Cell Monitoring - Ensures optimal charge and discharge for maximum life Over-charge, over-heat, over-load protection system. Compatibale with original Milwaukee M18 chargers and tools. 30 Days Money Back and 12 Months Limited Guarantee!