The Kliment Voroshilov (KV) tanks were a series of Soviet heavy tanks. At the time of the German invasion of the Soviet Union in World War II, about 500 KV tanks comprised a portion of Soviet tank forces which was clearly superior to German tanks of the period. The first Model 1939 was produced before war begun. Model 1940 (KV-1A) – used the F-32 76 mm gun and a new mantlet.