Oldenburg, Grand Duchy. A Model 1915 Enlisted Personnel Pickelhaube consisting of a blue enamelled Romanian Cross with clusters of nine gilt rays in eac on the left side is

on the left side is a machine embroidered NSKK insignia in silver thread on black embroidery backing (indicating Motorgruppe Niederrhein or Berlin)

Britain and Brazil later argued over the territory

on a seven-pointed star base

a length adjustment buckle on the right side strap

3) A Naval Submarine War Badge

Oldenburg, Grand Duchy. A Model 1915 Enlisted Personnel Pickelhaube consisting of a blue enamelled Romanian Cross with clusters of nine gilt rays in eac on the left side is(Oldenburg Pickelhaube M1915 fr Mannschaften). An Oldenburg Model 1915 Pickelhaube for Enlisted personnel, constructed of a black vulcan fibre shell. Situated atop the crown is an oxidized magnetic metal spike perforated along the neck with ventilation holes, and which is secured in place with a baseplate featuring four rivets. A bar of identical construction emanates from the back of the baseplate and extends down to a black vulcan fibre neck guard.