This 'Fat Man' case is similar to to the 'Fat Man' detonated at the Trinity Site on July 16, 1945 and air-dropped on Nagasaki, Japan on August 9, 1945. This case is on display at ground zero at the Trinity Site National Historic Landmark. It was used for training air and ground crews that handled nuclear weapons. 'Fat Man', named after the British war time Prime Minister Winston Churchill, is an implosion-type bomb and consists of a core of Plutonium-239, surrounded by explosives chemicals. The yield of 'Fat Man' was the equivalent of 21,000 tons of TNT and the average fireball temperature was 14,700 F (8,430 K). The Plutonium-239 core was built at Las Alamos, New Mexico and transported by car to the Trinity Site. The scientists that handled the ball of Plutonium, during bomb assembly reported it felt heavy for its size [(weight 14 lbs (12.2 kg), diameter of 89 mm (3.5 in)] and warm to the touch. The weight of 'Fat Man' was 10,800 lbs, the length was 128 inches, and the diameter was 60 inches. The wedge shaped fins at the back provide stability for the free-falling bomb. Four flanges,evenly spaced around the midsection anchored radar antennas,which bounced signals off the ground to determine altitude. 'Fat Man' was armed with multiple fusing mechanisms. including a barometric trigger. Four contact fuses were installed in the nose in case the airborne triggers failed. To the observers of the Trinity test. stationed at base camp, 10 miles distant, the heat of the fireball was felt instantaneously, it felt like a blast furnace, sound and shock waves arrived later. This picture was taken on 7 October 2017, Sig..