Mark 15 nuclear bomb
The Mark 15 nuclear bomb, or Mk-15, was a 1950s American thermonuclear bomb, the first relatively lightweight (7,600 lb (3,400 kg)) thermonuclear bomb created by the United States.
A total of 1,200 Mark 15 bombs were produced from 1955 to 1957. There were three production variants: Mod 1, Mod 2, and Mod 3. The design was in service from 1955 to 1965.
All three models were generally physically similar; weight of around 7,600 lb (3,400 kg), diameter of 34.4 to 35 in (87 to 89 cm), length of 136 to 140 in (350 to 360 cm). 
A missile warhead variant of the Mark 15, the W15 Warhead, was an ongoing project in the mid 1950s. It was canceled in early 1957. Before cancellation, it had been intended for use on the SM-62 Snark missile. Instead, the Snark ended up using the W39 (see below).
The W39 nuclear warhead and B39 nuclear bomb used a common nuclear physics package which was derived from the Mark 15. The experimental W39 devices were initially tested as the TX-15-X3 (which is identical to the W39 Mod 0 design).
Dropped and lost
|Wikimedia Commons has media related to Mark 15 nuclear bomb.|