M18, 18V, Red Lithium 2.0 Compact Battery Pack, Features Superior Pack Construction, Electronics & Performance To Deliver More Work Per Charge & More Work Over Pack Life, Offers 2.0 Amp-Hours Of Run Time , Battery Runs Cooler & Performs In Climates Below 0 Degrees/-18 Degrees Celsius, Compact Design Fits In Tight Work Spaces & Reduces User Fatigue, Powers Milwaukee M18 Cordless Power Tools.