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.
Science and technology in Russia
Famous Russian battle tanks include T-34, the best middle tank design of World War II, and further tanks of T-series, including the most produced tank in history, T-54/55, the first fully gas turbine tank T-80 and the most modern Russian tanks T-90 and T-14 Armata. The AK-47 and AK-74 by Mikhail Kalashnikov constitute the most widely used type of assault rifle throughout the world—so much so that more AK-type rifles have been manufactured than all other assault rifles combined. With these and other weapons Russia for a long time has been among the world's top suppliers of arms, accounting for around 30% of worldwide weapons sales and exporting weapons to about 80 countries.