Sturmpanzer IV Brummb r (SdKfz 166, Sturmgesch tz IV f r 15cm StuH 43) was a German self-propelled assault gun. Work on the design began in 1942 with a goal of creating a vehicle well suited for the demands of urban warfare. The gun was based on the PzKpfw IV Ausf. E and F and, later, Ausf. G. Initially, the vehicle carried 15 cm StuH 43 howitzer, which was later replaced by a bespoke 15 cm StuH 23/1 L/12 weapon. Brummb r went into production in 1943.