The Fritz X, also known as the Ruhrstahl X-1, was a precision-guided, armor-piercing bomb used with deadly effect by Germany in World War II against Allied ships in the Mediterranean. Based on the PC 1400 bomb, the Fritz X was dropped from an aircraft and guided by an operator using a joystick and transmitter. The spoilers on the cruciform tail controlled the bomb's trajectory.
Germany's first and most spectacular success with the Fritz X came in September 1943, when Do 217 aircraft sank the Italian battleship Roma and damaged the battleship Italia as they were sailing to surrender to the Allies. Air defenses against Do 217s, which had to fly slow and level while controlling the bomb, soon made further use of it impossible. The Smithsonian obtained this Fritz X from the U.S. Navy Bureau of Aeronautics.