Fat Man (nuclear weapon)
Fat Man was the code name for the second nuclear weapon used in the nuclear attacks against Japan during World War II. It was a plutonium implosion device, with an energy yield of approximately 12 kilotons of TNT equivalent. It was also designated as "Mark III" by the United States Army.
A Fat Man bomb was air-dropped on Nagasaki, Japan, on August 9, 1945. The Japanese surrendered shortly thereafter (August 14, 1945) and the war in the Pacific ended. Between 1947 and 1950, during the postwar era, 120 Fat Man bombs were produced and available for service.