In 1942, Soviet engineers developed the T-60-3. The vehicle, based on the T-60 light tank chassis, was armed with two 12.7 mm DShK heavy machine guns; but the prototype did not go into production because of flaws in the design. The SU-72 SPAAG and several other experimental vehicles based on the T-60 or T-70 light tank chassis and armed with 37 mm autocannon were also tested in 1942–1943. The ZSU-37 was based on the chassis of the SU-76M self-propelled gun (SPG) and armed with a 37 mm 61K anti-aircraft autocannon in an open-top rotating armoured turret. The vehicle entered production in February 1945 and was in small-scale production until 1948.