Grw. 81mm is a German Artillery unit.
Schwere Granatwerfer 34 was the standard heavy mortar of the German Army. These were used in the 8-cm Mortar Section of the late 1943 Grenadier Rifle Company. With the reorganization in mid-1944 8-cm were reorganized into a 8-cm Mortar Platoon of three section with two Mortar Squads in the Heavy Company along side Grw. 120mm Platoon and a Heavy Machine Gun Platoon.