The change was the liner. The early liner was replaced.Which left the distinctive slots on each side and the now unused bolt holes. Originals run in the 5 digits in value and reproductions are not easy to find. Helmet size around 59-60 liner. The item "WWII GERMAN M37 Paratrooper HELMET WithHand Aged Paint Work and Liner" is in sale since Wednesday, March 24, 2021. This item is in the category "Collectibles\Militaria\WW II (1939-45)\Reproductions\Germany". The seller is "gafrika42" and is located in Lakeville, Minnesota. This item can be shipped worldwide.