The M18 REDLITHIUM XC 4.0 extended capacity battery packs construction, electronics and performance, help deliver more work per charge and more work over pack life than any battery on the market. It offers 4.0 amp-hours of runtime. With Milwaukee durability built into each pack, this battery runs cooler and performs in climates below 0°F/-18°C.Milwaukee’s REDLINK Intelligence provides the battery overload protection to prevent you from damaging your cordless power tools in heavy-duty situations. While the discharge protection prevents cell damage, the temperature management system and individual cell monitoring help maximize battery life. 48111840 48-11-1840