The BT-SV is a Tier III Soviet Light Tank. It is currently not available in the in-game store.
The tank has very heavy armour, coupled with sloping, which allows it to resist practically every other tier 3 gun in game, save for a few. The engine is also very powerful, and gives the tank extremely fast acceleration, yet does not turn very well, so attack paths must be chosen well, and lakes and bodies of water should be avoided, while in reality this tank was amphibious, this is not the case in World of Tanks. With thick side armor and side skirts, this tank can also sidescrape effectively and as a inaccurate gun like many Soviet tanks.