From the website:
BT-7 Fast Tankovy Company (SBX20) includes five BT-7 Tanks with optionall AA MG & one Tank Commander sprue.
Once the Soviet infantry had broken through the enemy lines, deep operations began. These called for tank and cavalry forces to advance rapidly to take objectives up to a hundred kilometres (sixty miles) or more behind the front, surrounding the enemy and destroying them. For this role the Red Army looked at a tank designed by an American, Walter Christie, and like the T-26, built unlicensed copies in huge numbers as the BT series of fast tanks.