Heavy tank
The Char 2C was one of the largest tanks ever produced. At the start of World War II, France and the Soviet Union were the only countries to have inventories of heavy tanks, such as the Char B1, T-35, and KV-1. The Matilda II was designed under the British infantry tank concept which is similar to the heavy tank having thick armor and weighing more than their other tanks. It’s usually separate because they have less firepower with their cruiser tanks (comparable to mediums) at the time having the same main armament but more machine guns. Later war examples were the German Tiger I and II, as well as the Soviet IS series. Note that "heavy" versus "medium" is more a question of tactical roles than weight; the Panther, for example, was a "medium" tank that outweighed most Allied "heavy" tanks.
Valentine tank
The Valentine was extensively used in the North African Campaign, earning a reputation as a reliable and well-protected vehicle. The first Valentines went in action with the 8th Royal Tank Regiment in Operation Crusader. The tank first served in Operation Crusader in the North African desert, when it began to replace the Matilda Tank. Due to a lack of cruisers, it was issued to armoured regiments in the UK from mid-1941. The Valentine was better armed and faster than the Cruiser Mk II. During the pursuit from El Alamein in late 1942, some tanks had driven more than by the time the Eighth Army reached Tunisia.
The Valentine shared the common weakness of the British tanks of the period, its 2-pounder gun lacked high-explosive (anti-personnel) ammunition and soon became outdated as an anti-tank weapon. Introduction of the 6-pounder in British service was delayed until the loss of equipment in France had been made good, so the 2-pounder was retained longer. The small size of the turret and of the turret ring meant that producing mountings for larger guns proved a difficult task. Although versions with the 6-pounder and then with the Ordnance QF 75 mm gun were developed, by the time they were available in significant numbers, better tanks had reached the battlefield. Another weakness was the small crew compartment and the two-man turret. A larger turret, with a loader position added, was used in some of the 2-pounder versions but the position had to be removed again in variants with larger guns. Its relatively low height was an advantage in a battlefield with little cover, allowing it to take up a "good hull-down position in any convenient fold in the ground".