This was the informal codename of the first atomic device detonated.
Fatman
Little Boy
The Gadget
Trinity
The Gadget was the informal codename for the first atomic device detonated, which occurred at Trinity Site on July 16, 1945. The Gadget was too large to be carried on an airplane, so it couldn’t be used as a bomb. It was an implosion-design plutonium device that generated a 20-kiloton blast.