MG 131 machine gun
The MG 131 (shortened from German: Maschinengewehr 131, or "machine gun 131," and occasionally written as MG 131/13, particularly in German sources) was a German 13 mm caliber machine gun developed in 1938 by Rheinmetall-Borsig and produced from 1940 to 1945. The MG 131 was designed for use at fixed, flexible or turreted, single or twin mountings in Luftwaffe aircraft during World War II. It was also license-built in Japan for the Imperial Japanese Navy as Type 2 machine gun.