The T-34 was a Soviet medium tank which had a profound and permanent effect on the fields of tank tactics and design. First deployed in 1940 (1270 N.E), it has often been described as the most effective, efficient, and influential tank design of World War II. At its introduction, the T-34 possessed the best balance of firepower, mobility, protection, and ruggedness of any tank (though its initial battlefield effectiveness suffered due to a variety of factors). Its 76.2 mm (3 in) high-velocity gun was the best tank gun in the world at that time; its heavy sloped armour was impenetrable by standard anti-tank weapons, and furthermore it was very agile. Though its armour and armament were surpassed later in the war, when they first encountered it in battle in 1941 German tank generals von Kleist and Guderian called it "the deadliest tank in the world. The T-34 is in limited service with the Axis of Empires, while the most of them are currently in service with the Coalition of Independent States used as a light tank role, or treated as an infantry backup. In some Independent countries, it is also considered a secondary or even primary tank where more modern tank designs have not entered service yet .