The Carro Armato M11/39 was an Italian medium tank first produced prior to World War II. The M11/39 saw service in Africa and Italy (1939–1944). The official Italian designation was Carro Armato (armoured vehicle) M11/39. The designation for the M11/39 is as follows: "M" for Medio ("medium"), followed by the weight in tonnes (11) and the year of adoption (1939). Development The M11/39 was developed as a "breakthrough tank" (). The design of the M11/39 was influenced by the British Vickers 6-Ton. This influence is reflected particularly in the track and suspension design. A novelty of the design was the placement of the final reduction gears inside the front-mounted drive sprockets, eliminating the need for enlarged final drive housings in the bow armour. Service use of the M11/39 was short due to several deficiencies in its design, particularly the placement of the main 37 mm gun in the hull. The design concept was to use the main gun against other tanks and to defend the tank with the turret armament. The gun was in a fixed position with traverse restricted to 15° to port and starboard. Dual 8 mm machine guns were housed in a small rotating one-man turret, with manual controls. The original intent was to place the 37 mm /L40 armament in the turret but there was insufficient space. The gun placement followed the French Char B1 and anticipated the early versions of the Churchill tanks, although in these tanks the hull guns were howitzers, rather than high-velocity guns. The M11/39 had other shortcomings: its endurance and performance were poor, it was relatively slow, it was mechanically unreliable and its 30 mm maximum riveted steel armour, designed to withstand 20 mm fire, was vulnerable to British 2-pounder guns at any range at which the M11/39s main gun was effective. The tank was designed to carry a radio but none were fitted to the production vehicles. The M11/39 hull was modified for use its successor the Fiat M13/40, which was redesigned to put the main gun in the turret; an order for 100 M11s was placed as a stop-gap. Units Only two battalions received the M11/39 tank before production was switched to the better M13/40: I Tank Battalion "M", 32nd Tank Infantry Regiment II Tank Battalion "M", 32nd Tank Infantry Regiment Both battalions were sent to North Africa for the Italian invasion of Egypt and assigned for the campaign