The M12 REDLITHIUM XC 4.0 Extended Capacity Battery Pack features improved construction, electronics and performance Its 4.0 amp-hour runtime delivers more work per charge. With Milwaukee durability built into each pack, this battery runs cooler and performs in climates below 0°F/-18°C. Milwaukee’s REDLINK Intelligence gives the battery overload protection to prevent you from damaging your cordless power tools. While discharge protection prevents cell damage. The temperature management system and individual cell monitoring help maximize battery life. 48112440 48-11-2440