After the success of the 15cm Sturm-Infanteriegeschutz 33 in Stalingrad, Panzer IV chassis was developed as the next Sturmpanzer to provide direct infantry fire support, especially in the urban areas. The Sturmpanzer IV had a fixed armored superstructure housing a 150mm StuH 43 L/12 gun. This 150mm StuH 43 was developed from the successful Sig 33 15cm infantry gun. It was capable of firing both high explosive and shaped charge rounds. The Sturmpanzer IV's superstructure and StuH 43 gun was modified in subsequent versions following feedback and comments received from frontline reports and comments. Four versions or Series were produced with each Series incorporating improvements. Production began in May 1943 and continued until March 1945. More than two hundred Sturmpanzer IVs were built in total. The first Series was built on Panzer IV ausf.D, usf.E and ausf.F chassis. The Sturnpanzer IV joined the action on the Eastern Front and was rushed to participate in the Battle of Kursk. On the Western Front, they were used in Italy and joined the German final offensive at the Battle of the Bulge.