The F-4E was the most numerous and multirole USAF Phantom II version, powered by two afterburning General Electric J79-GE-17 turbojets and fitted, for the first time in the family, with an internal 20 mm M61A1 Vulcan cannon with 639 rounds in an undernose fairing (which lengthened the fuselage compared to earlier versions). It reached Mach 2.21 at 10,973 m and carried up to 7,257 kg of ordnance on the centerline and four underwing hardpoints, plus AIM-7 Sparrow and AIM-9 Sidewinder missiles. It was the basis for numerous export sales (Israel, Germany, Greece, Turkey, Japan, South Korea, Egypt and Iran, among others) and for the F-4G Wild Weasel conversion.