The BT tank design was based on the American Christie convertible tank design, in that they could drive without tracks being fitted.
During the 1930's it was the most numerous tank in the world together with its stablemate the T-26.
Its combat history started with the Spanish civil war in 1937 and variants were still in services at the end of 1945, however the start of the Great Patriotic war and the invasion by the German army in 1941 saw the bulk of the BT's destroyed and by 1942 any surviving vehicles being withdrawn from the frontline and replaced with better tanks.
The BT design was a very good design especially in the early 1930's and during its development many improved features would be incorporated into other legendary tank designs.
Though its design was good its manufacturing was not, leading to problems with reliability and poor armour combined with poor tactics saw most wiped out in 1941.