The Czechoslovakiam helmet M/34. The full number of such helmets in Finnish Army (former German war booty) was up to 50000. Such helmets were used during 1941-44. This item was found on the75mm PAK 40 positions in June 1944 battlefields.
Previous photos - the helmet soon after unearthing and first cleaning. Some paint was clearly seen mostly in the inner side - it helped during the restoration.
The inner leather parts were marked 1938. (The fifth leaf of it was lost by the previous owner somewhere on roads of the war.)
After the restoration. It looks almost the same when Finnish soldier lost it during the retreat to Viipuri/Viborg during 19.06.44...