This is an original German M16 helmet, used in Bulgarian royal army. It was made in Germany during the WWI, to Bulgarian royal army’s order. Bulgaria become ally of Germany in both world wars, so bigger part of military equipment was made in Germany or countries allied.
The helmet here is witness of the two world wars and survived the 45 years communist rule in Bulgaria when all German relics of the war were taken and destroyed. Now a day only single pieces can be found in such authentic condition and are highly wanted for private collections ( where this shell comes from).
The helmet was made in WWI. After the war in 1930s it received new liner in order to be used again. There is also another layer of green paint and Bulgarian army decal that can be dated by the same period. The original layer is still visible at some places.
The liner is of old Bulgarian model typical for the pre-war period.
The helmet's rear is stamped "ET 64" standing for the German producer Eisenhüttenwerk Thale, ?hale/Harz . Another number is stamped on bottom of the helmet.
Size : EU 57-58
A very precious helmet , more and more rare to find!