ORIGINAL 1937 GERMAN M31 LINER. MODIFIED BY NORWEGIANS POST WAR. I’ve had this liner reviewed by collectors in the US and abroad who have experience in authentic German Helmets and Liners. The consensus was unanimous, and the details are as follows. An authentic 1937 M31 early single ply aluminum system for the M35. The liner material is goat which aligns with pre-1940 liners. There are 3 stamps although all are very light and only partially legible. 1 A stamp on the aluminum liner showing 1937 as the date & name of manufacture. 2 A 64nA/57 stamp on the liner showing size. But only the outline is visible, and barely. All good signs of provenance. The leather liner is cracked in places on the rim and the fingers are a little stiff but overall a great original liner. Norwegian modifications: – The liner was removed and dyed red for use by the Norwegian Army post WWII. Evidenced by the brass rivets and some red dye spots by the rim. It appears someone recently removed the red dye to bring it back to original. There is a 1.5″ x 2″ welded piece of aluminum 4 plcs. On the left side. Behind that the liner was cut so it could be made a smaller size 62. I took a measurement on the outside diameter which came out around 63cm (See pic). Strap: The strap is a perfect example of early German M35 Straps. The leather is still subtle. The strap can be unbuckled with no fear of further damage. It’s in remarkably good shape. Please look at all of the pictures as the best indicator of condition. There are not many of these real liners left in circulation. If you have any questions, please feel free to contact me.