They stopped producing in 1940 during WW2 because after their attack on the Finnish it was declared that their thin armor was incapable of stopping shells from Finnish anti tank cannons, but they kept serving the war.
They too were very suseptable to flames and were slow. However, these were produced in mass numbers.
I may need some fact checks because I got these from Wikipedia.Their stats:
Attack:13 (Had the same gun as BT-7)