Entering production in 1963 as the Mk 57, the bomb was designed to be dropped from high-speed tactical aircraft. It had a streamlined casing to withstand supersonic flight. It was 3 m (9 ft 10 in) long, with a diameter of about 37.5 cm (14.75 in). Basic weight was approximately 227 kilograms (500 lbs). The B57 used the Tsetse primary design for its core design, shared with several other mid- and late-1950s designs. The B57 was produced from 1963 to 1967. After 1968, the weapon became known as the B57 rather than the Mk 57. 3,100 weapons were built, the last of which was retired in June 1993.