The stamped sheet steel construction helmet retains about 98% of its original feldgrau paint. Beautiful dome stamp to the inside center of the helmet. The reverse, interior neck guard apron has a stamped serial number, "3757", and the manufacturers code and size "CKL66", indicating manufacture by Eisen-und Hüttenwerke, AG Thale/Harz, size 66. Near MINT shell. The first "modern" steel helmets were introduced by the French army in early 1915 and were shortly followed by the British army later that year. With plans on the drawing board, experimental helmets in the field, ("Gaede" helmet), and some captured French and British helmets the German army began tests for their own steel helmet at the Kummersdorf Proving Grounds in November, and in the field in December 1915. An acceptable pattern was developed and approved and production began at Eisen-und Hüttenwerke, AG Thale/Harz, in the spring of 1916. These first modern M16 helmets evolved into the M18 helmets by the end of WWI. The M16 and M18 helmets remained in usage through-out the Weimar Reichswehr era and on into the early years of the Third Reich until the development of the smaller, lighter M35 style helmet in June 1935. In an effort to reduced construction time and labor costs minor modifications were introduced in March 1940 resulting in the M40 helmet. Further construction modifications were undertaken in August 1942 resulting in the M42 helmet. Originally the Third Reich national tri-color helmet decal was introduced on March 14TH 1933 for wear on the left side of the helmet to replace the Reichswehr era state shield insignia. Regulations of February 17TH 1934 introduced the Wehrmacht eagle decal and the national tri-color decal was shifted to the right side of the helmet with the Wehrmacht eagle decal positioned on the left hand side. Regulations of March 21ST 1940 dictated that the national tri-color decal was to be removed from all helmets and further regulations of August 28TH 1943 abolished the Wehrmacht eagle decal and dictated that it was also to be removed from all helmets although the directives were not completely adhered to.