Pre WW2 Soviet Russian experimental M36 steel helmet

This is a extremely rare experimental Russian helmet. Pre WW2 Soviet Russian experimental M36 steel helmet designed for heavy howitzer artillery, made by Izhora factory "Izhorskiy zavod" in Leningrad, the factory name is "Izd 187/35". The helmets were produced, then approved by Russian army, and were not accepted. After that all helmets came back to the factory stock. In the Finnish winter war 1939-40.y, they came to the army again and were used in 4-th division of 168 high-power artillery regiment(4 division 168 artilleriyskogo polka bolshoi moshnosti) which was equipped with 203-mm howitzers. Some of this helmets were found in the factory Nr 185 - "Kirovs factory" (Russia), on the stock nr 3., a couple of year ago. A very, very rare item for only serious collectors!