The ZPU range of anti-aircraft guns is a family of towed Anti Aircraft guns developed in 1945 at the end of the Second World War, entering into service in 1949. the ZPU range of Anti Aircraft guns mounts the KPV-14.5 heavy machine gun firing the Soviet-designed 14.5×114mm-caliber round each gun is capable of firing up to 600 rounds a minute air-cooled with quick-change barrels. the KPV is capable of firing a range of ammunition High Explosive Incendiary – Tracer (HEI-T) or Armour-Piercing Incendiary (API) bullets. designed to engage low flying aircraft with a horizontal range of 3000 meters and a vertical range of 2000 meters. the ZPU 1 mounting one gun and the ZPU 2 mounting two guns are on a single axle towed trailer whereas the ZPU 4 mounting four KPVs is mounted on a two-axle trailer.