When the German Wehrmacht began to rebuild in the 1930s, they procured whatever helmets were available.This included depot stocks of WWI M16, M17 and M18 helmets. These helmets are referred by collectors as «transtionals». Early transitionals retained their original WW1 paint, liners and chinstraps but were fitted with TR (Third Reich) decals. Subsequently the helmets were upgraded with smooth paint (the same field gray found on the M35), M31 liners, modern chinstraps and a set of decals; these are referred as classic transitionals. As the war progressed and the manufacturing demand for helmets increased, German forces in occupation or garrison duties were often equipped with remaining stocks of WWI helmets or WWI transitionals. These helmets were reissued with textured paint, M31 liners, modern chinstraps and a decal on the left side only.
Many period photos from the invasion of Norway in April 1940 show German soldiers wearing transitionals. Those transitionals that remained in Norway during the occupation received new paint and a new look by the units using them. The author has found a great variety of transitionals in Norway and they are more common than rare.
The right side of the helmet above. An ET style decal has been placed where the national shield should have been. Notice the placement of the rivet and the vent "horn”. Both were stamped too high and to close too the front compared to the left side. A manufacturer flaw which is seen sometimes in WWI and WW2 helmets.