This Russian helmet retains most of its green paint and the original chinstrap. This model with 6 rivets and the 3 pads liner was produced since 1940 and adopted by Red Army until '60s. I don't see markings stamped inside indicating the year of manufacturing, only a star in a circle meaning that the helmet was refurbished at one point. So I assume this is a WW2 era helmet that saw use long after the war.

€40