2 pack, m18 red lithium xc, high capacity battery, 3.0a hour - 54w hour battery, delivers long life & run time with fade free power, battery fuel gauge displays remaining run time Milwaukee red lithium intelligence, overload protection prevents user from damaging their cordless power tool investment in abusive situations, temperature management system keeps battery in ideal temperature range to provide maximum life, individual cell monitoring ensures optimal charge & discharge for maximum life, discharge protection prevents cell damage from over-discharge, integrated weld frame, cell separator, impact & vibration protective rubber, for use with Milwaukee m18 cordless tools.