During WWII, the Soviet built a self-propelled gun based on the T-34 chassis. The self propelled gun was named the SU-85. The "SU" abbreviation stands for "Samokhoknaya Ustanovka" which means "self-propelled gun" and the 85 stands for the 85mm D-5T gun. The SU-85 had a crew of four men. Despite the fact that the SU-85 was a self propelled gun, it was worthy of the title tank destroyer. The tank was first deployed in battle in December 1943 after the liberation of Kiev. The Russian military incorporated 21 SU-85 vehicles into an artillery battalion under the control of the corps and 31 into an artillery regiment under control of the tank army. By the mid 1940s, the Su-85 was replaced by the SU-100, which carried a 100m gun.