The original StuG III was actually more of an infantry support vehicle rather than a true self-propelled artillery piece. On December 1943, Hitler ordered the StuG III superstructure fitted to the PzKpfw IV chassis. It was an interim design until Jagdpanzer could begin production. Later models were upgraded with the longer L/48 gun, up to 80 mm of frontal armor, Zimmerit anti-magnetic coating and side skirt armor. It's primary role changed to that of a tank hunter (Jagdpanzer).
