BAI, or BA-I means "Broneavtomobil-Izhorskiy" - Izhorskiy Armored Car
Destroyed BAI armored car [3]
Rem. AMVAS: If to follow data provided by Mr. Litvin, who sent me this photo. It was represented in Finnish album. So this can be Karelia
Upper: BAI armored car on Ford-Timken chassis
Lower: BAI-M armored car on GAZ-AAA chassis [2]
In 1938-40 all remaining BAI vehicles were rebuilt to the BAI-M version.