The s.IG.33 auf Fgst. Pz.Kpfw.III (Sfl) was a heavy infantry gun mounted on a StuG.III chassis. The Sturm-Infanteriegeschütz 33B featured a 15cm s.IG.33/1 gun in its boxy superstructure. Just 24 of these 21-tonne weapons were produced by Alkett from December 1941 onwards. They utilized a StuG.III Ausf.E or F/8 chassis.

Five crewmen operated this self-propelled gun that was used exclusively on the Eastern Front. Half fought in the bloody Battle of Stalingrad from October 1942 onwards, where their heavy guns could effectively demolish buildings in the bitter urban combat.

The remaining vehicles didn’t reach Stalingrad because the German 6th Army was encircled by that time, so instead they deployed with the 23rd Panzer Division.