German mountain gun of WorldWarII 7.5 cm Infanteriegeschütz 37 (7.5 cm le.IG 37) 7.5 cm Infanteriegeschütz 42 (7,5 cm le.IG 42) 7.5 cm leichtes Infanteriegeschütz
ST-5 caliber 20 mm (.79 in) • 2 cm Flak 30/38/Flakvierling – the most produced German artillery piece of WorldWarII, based on Russian 2-K AA gun design