The Kliment Voroshilov (KV) tanks were a series of Soviet heavy tanks named after the Soviet defense commissar and politician Kliment Voroshilov and used by the Red Army during World War II. The KV series were known for their extremely heavy armour protection during the early part of the war, especially during the first year of the German invasion of the Soviet Union.
KV-220 (Object 220) – Was an experimental tank based on KV-1. Longer chassis (7 rollers per side). Armor – 100mm. New 850 hp V-2SN engine with turbocharging. New diamond-shaped turret and 85mm F-30 cannon. One prototype was constructed in 1941. The tank was lost in battle.