SU 122-54 (Obyekt 600) - Self-propelled 122mm gun, based on the T-54A and sometimes known as IT-122. Between 1955 and 1957, 77 vehicles were built with minor differences between production lots (different commander's cupola etc.). The SU-122-54 had a modified chassis, with small spaces between the first, second and fourth pair of wheels and a large gap between the third, similar to the T-62's and a superstructure, built into the hull, housing the 122 mm M-62-T gun for which the vehicle carries 32 rounds. The secondary armament consisted of two KPVT heavy machine guns, one mounted as an anti-aircraft machine gun near the commander's hatch and the other mounted coaxially with the main gun. The vehicle carried 600 rounds for the machine guns. The main gun has a fume extractor positioned right behind the muzzle brake, some vehicles did not have the fume extractor. Other variations included a different commander's cupola.