The MG 81 was a belt fed 7.92 x 57 mm machine gun for fixed or flexible installations in World War II Luftwaffe aircraft, replacing the older drum magazine-fed MG 15. The MG 81 was developed by Mauser as a derivative of their successful MG34 infantry machine gun. Development focus was to reduce production cost and time and to optimize for use in aircraft. Developed in 1938/1939, it was in production from 1940 to 1945.