One of the great oddities of the Third Reich arsenal, the "krummlauf" device was a cause of a great deal of confusion on the part of the Allies when examples were captured. As a mechanical concept, curving a barrel to change the path of a bullet seems like a bad idea, but it actually worked; the extension would shift the trajectory of the bullet several degrees off its original axis without excessive loss of velocity. The first examples were built by the Germans for test-firing high-powered anti-aircraft weapons, allowing test shots at elevated angles, and were later adapted for field use. A krummlauf-equipped assault rifle or machine gun could be used by infantry to fire over barricades or around corners without exposure or mounted in compact ball turrets on tanks and vehicles as a point defense weapon against sappers and enemy infantry. This particular krummlauf was manufactured by modifying a K-98 grenade launcher into a mounting point for a curved barrel, which is fitted with a blade front sight; on the more standard Type I krummlauf, this front sight aligns with the standard rear sight via a prismatic lens, which is not included. The barrel is marked "VZ21" next to a large hole (a common fate for field-used krummlaufs), and the underside of the clamp is marked "fnh" and "WaA76" (Boehmische Waffenfabrik, aka CZ). Two additional curved barrels (sans mounting hardware) are included, each with an 8mm bore; one of them has a slot cut through to expose the rifling, and neither is marked.

Fair overall. The device shows a bright appearance overall with mild spotting and handling marks, and both extra barrels show a mixed brown/gray patina.