A new, fully enclosed, and heavily armored boxy casemate superstructure was built on the chassis of the Sturmgeschütz III.

[1] Trojca and Jaugitz contend that all twenty-four were built by Alkett starting in September 1942 from repaired Sturmgeschütz III Ausf.

[2] The first dozen were delivered by the end of October 1942 and assigned to Sturmgeschütz-Abteilungen (Assault Gun Battalions) 177 and 244, then fighting in Stalingrad.

The remaining dozen vehicles could not be delivered to Sturmgeschütz-Abteilungen 243 and 245, also fighting in Stalingrad, after the Soviets surrounded the German 6th Army on 21 November.

Of the five remaining in September 1944, a single vehicle survives at the Kubinka NIIBT Research Collection near Moscow.