The T-28 (designated with a hyphen to prevent confusion with the T95) is a Soviet medium tank. It is among the world's first medium tanks, and it is a very mobile one at that, which makes up for its very large hull and rather poor armour. It is the only medium tank so far with three turrets, one main turret and two secondary. As well as a finished production, the T-28 was also the basis for the T-35, which had one primary turret, two medium turrets, and two small turrets. The first prototype was built in 1931 and it entered production in late 1932. It was mainly an infantry support tank and was built to break through fortified defenses.