The
STZ-5 artillery tractor was a product of the
Stalingrad Tractor Factory (STZ) (Russian: Сталинградский тракторный завод) from 1937 to 1942 in the
Soviet Union. The tractor was designed to tow division to corps level guns and howitzers of 8 tonnes and less. The STZ-5 was one of the few
artillery tractors specifically designed by the Soviet government for its role. With over 9900 built, it was the most-produced Soviet ‘military’ tractor during the war.
From Wikipedia article: https://en.wikipedia.org/wiki/STZ-5