The AT-1 is the very first Soviet TD available to the player.
It has extremely weak armour, even for its tier and can be
penetrated by most of the tanks it will come up against;
however, its gun is one of the best for tier 2, and with its
high RoF and Damage not many tanks are in your sights
for long before they burst into flames. this will help you to
cope with the higher tier Russian TD's as they also have paper
armour and big guns. Such as the Soviet teir 8 TD: the ISU-152, with
its amazing 152mm BL-10 cannon but weak armour all round.