The tank destroyer code-named SDP 40 Zadymka was designed with the goal of destroying heavily armored combat vehicles and reinforcing prospective medium tanks. The gun caliber was large enough for the vehicle to be used as an assault SPG. Its engineers drew on British experience in manufacturing hulls with large cast parts. Since the ammunition could not fit in the cabin, the solution was to make a niche partly covering the engine compartment. The work did not progress beyond schematic blueprints.