WW1 GERMAN PRUSSIAN OFFICERS/SNCO SPIKE HELMET (PICKELHAUBE)
This helmet is more than likely a Senior Non-Comissioned Officers (SNCO) helmet due to the style of liner which is an OR's (Other Ranks) pattern which was an Army issued helmet as opposed to an Officers pattern liner which were private purchased helmets.
The helmet is in very good condition with brass fittings and unit markings to the rear neck flap.