Developed on a PzKpfw IV chassis that was lengthened and used the drive assemblies, track, and transmission from a PzKpfw III. The first prototype appeared in 1941. The engine was moved to the center as the fighting compartment was in the rear. Range of 12,550 meters. Early vehicles had muzzle brake installed but it was found that these were unnecessary and were removed from production. Early models had the glacis plate extended and a compartment for the driver was made on the left side.
