Diorama rear perspective, various names designated this self-propelled assault gun, including Sturmpanzer IV (referred to Panzer IV chassis), Sturmpanzer 43 (referred to 1943 production year), Brummbar (Grizzly Bear), Stupa (shorten name for Sturmpanzer). Three German helmets hung outside to converse crew space, its design dates back to WW1-era for both ballistic and overhead artillery shrapnel protection. German Camouflaged Helmets Gallery - www.german-helmets.com/Camouflage%20Gallery.htm

Late-production Stupas called Abschlusserie (final version), with modifications in angled superstructure, front ball-machine gun mount, commander copula added. Schurzen (armor skirts) was standard equipment to war's end, but by late-1944 it was changed from solid armored plates to armor mesh design (defense against shaped-charged warheads). Zimmerit anti-magnetic paste was no longer applied by late-1944. Shaped charge - en.wikipedia.org/wiki/Shaped-charge

Inset 1 : Knocked-out Stupa on Eastern Front with shrapnel scaring and shell impact marks. Note large hole entrance in front of vehicle, used by German frontline troops to shelter underneath vehicle from the environment and enemy artillery strikes. Abandoned tanks are quite resilient against direct artillery hits, hence offered excellent protection, both Germans and Soviets used this tactic.

Schurzen (solid plates or armor mesh) created small spacing away from vehicle hull, thus forcing premature detonation of enemy shaped-charged warheads (designed to burn through armor and spew molten debris into crew compartment), thereby reducing 75% of its energy before hitting the hull. However, if enemy rounds were fired from close distance, no amount of protection could forestall vehicle from being disabled or destroyed outright. Famed WW2 shaped-charged weapon was German hand-held Panzerfaust. Panzerfaust WW II German Infantry Anti-Tank Weapons - www.geocities.com/Augusta/8172/panzerfaust1.htm