The W31 was an American nuclear warhead used for two US missiles and as an atomic demolition munition.
The W31 was produced from 1959, with the last versions phased out in 1989.
All versions were roughly the same dimensions and weight: 28–30 in (710–760 mm) in diameter, 39–39.5 in (990–1,000 mm) long, and weighing 900–945 lb (408–429 kg). The W31 is a boosted fission nuclear bomb.[1]