"Karl-Gerat" (040041) (German literally "Karl-device"), also known as Thor and Morser Karl, was a World War II German self-propelled siege mortar (Morser) designed and built by Rheinmetall. It was the largest self-propelled weapon to see service. Its heaviest munition was a 60 cm diameter, 2,170 kg shell, and its range for its lightest shell (1,250 kg) was just over 10 km. Each gun had to be accompanied by a crane, a heavy transport trailer, and several modified tanks to carry shells.