Set of 2 barrels for German 7,92 mm MG.17 aircraft machine guns. The MG 17 was installed in the Messerschmitt Bf-109, Messerschmitt Bf-110, Focke-Wulf Fw-190, Junkers Ju-87 'Stuka', Junkers Ju-88C Nightfighter, Heinkel He-111, Dornier Do-17/Do-215 Nightfighter, Focke-Wulf Fw-189 and many other aircraft. Many MG 17s were later modified for infantry use, as the Luftwaffe replaced them with the heavier-calibre MG 131, which replaced both the MG 15 in bomber defense applications and the MG 17 as the standard fighter's forward-firing offensive armament (unless the machine guns were replaced by autocannons, such as the MG 151/20, altogether). Official numbers of conversions was about 24,271 by January 1, 1944, although additional conversions may have been done as well (thanks to Wikipedia)