Mark 7 "Thor" (or Mk-7) was the first tactical fission bomb adopted by US armed forces. It was also the first weapon to be delivered using the toss method with the help of the low-altitude bombing system (LABS). The weapon was tested in Operation Buster-Jangle. To facilitate external carry by fighter-bomber aircraft, Mark 7 was fitted with retractable stabilizer fins. The Mark 7 warhead (W7) also formed the basis of the 30.5 inches (775 mm) BOAR rocket, the Mark 90 Betty nuclear depth charge, MGR-1 Honest John rocket, and MGM-5 Corporal ballistic missile. It was also supplied for delivery by Royal Air Force Canberra aircraft assigned to NATO in Germany under the command of SACEUR. This was done under the auspices of Project E, an agreement between the United States and the UK on the RAF carriage of US nuclear weapons. In UK use it was designated 1,650 lb. H.E. M.C. The Mark 7 was in service from 1952 to 1967 with 1700–1800 having been built. Mark 7 nuclear bomb - Wikipedia