The McDonnell Douglas F-4 Phantom II a two-seat, twin-engined, all-weather, long-range supersonic jet interceptor fighter/fighter-bomber originally developed for the United States Navy by McDonnel Aircraft. It first entered service in 1960 for the U.S. Navy. It was also adopted by the U.S Marine Corps and the U.S Air Force and by the mid-1960s had become a major part of their respective air wings. The Phantom is a large fighter with a top speed of over Mach 2. It can carry over 18,000 pounds (8,400 kg) of weapons on nine external hardpoints, including air-to-air and air-to-ground missiles, and various bombs. The F-4, like other interceptors of its time, was designed without internal cannon, but later models incorporated a M61 Vulcan rotary cannon. Beginning in 1959, it set 15 world records, including an absolute speed record, and an absolute altitude record.