The SU-100 is a World War II Soviet tank destroyer armed with the 100mm D-10S gun. It was developed from the T-34/85 medium tank by the Uralmashzavod design bureau in late 1943/early 1944 as a modified version of the earlier SU-85, which did not have sufficient fire power to fight German heavy tanks. In 1951, licensed production of the SU-100 started in Czechoslovakia. A total of 4,967 units of the SU-100 were produced across both countries. The first combat use of the SU-100 took place in January 1944. Afterwards, the SU-100 played an important role on all Soviet fronts in late WWII. In later years many Soviet allies used the SU-100 for their armies.