M18 Battery for Milwaukee 18V REDLITHIUM 4.0Ah XC Battery Pack 48-11-1852 48-11-1820 48-11-1815 48-11-1850 (2Pack) 2Packs18V M18 Replace REDLITHIUM XC 4.0 Extended Capacity Battery Pack for Milwaukee. 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. Best-in-class construction: Offers long-lasting performance and durability.All-weather performance: Delivers fade-free power in extreme jobsite conditions. Electronics control charge & discharge analytics to optimize performance and extend life. 30 Days Money Back and 12 Months Limited Guarantee!