In 1935, Erich von Manstein of the German Army General Staff, in a letter to General Ludwig Beck, described the idea of building assault artillery to support attacking infantry units. Five prototypes of the "zero" series were manufactured in 1937. Early modifications from Ausf.A to Ausf.F/8 were produced until December 1942.
The technical characteristics shown are for the Siege mode
Characteristics are specified for a vehicle with crew members trained to 100%.