Never I have seen so marked WW2 era Russian pilots helmet before. I do have many WW2 era Soviet Air Force photos showing these late WW2 era Russian leather helmets and with this kind plug instead of full bakelite one.
This helmet is in a good condition for it's age and extremely rare. He said that this helmet is post WW2 era.. I have some 50 WW2 era Soviet Air Force photos dated mostly 1944 and some 10 photos are showing similar helmets like mine in service during WW2. Here are also similar helmets and at least one is 1943 or 1944 dated... Third link is saying that this helmet is mid-late WW2 era Soviet flying helmet.I have seen a couple Soviet helmets with LKpS/W100 style metal ear cup covers and they are dated 1940, so Russians copied German helmets already before The Great War 1941-45. This item is in the category "Collectibles\Militaria\WW II (1939-45)\Original Period Items\Russia\Hats & Helmets". The seller is "lipfertjg52" and is located in this country: FI. This item can be shipped to North, South, or Latin America, all countries in Europe, all countries in continental Asia, Australia.