Model 1915 Preußen Kürassier Metalhelme
 
Model 1915 Preußen Kürassier Metalhelme. The helmet is maker marked "Lachmann Berlin" on top the skull interior. Lachmann helmets are very distinctive with the rear tail drooping down at almost 90 degrees. Steel helmets for the Preußen Kürassier followed the 1915 regulations however, this example has grey painted steel fittings, which are normally grey oxidized steel fittings.
 
A side view of the Model 1915 Preußen Kürassier Metalhelme. Note how the rear tail droops down at almost 90 degrees, which is unique to Lachmann manufactured helmets.
Like the earlier Kürassier Metalhelme, the liner of issued M1915 Metalhelme was of leather with rounded "tongues" perforated at the ends for a leather string to adjust the fit.

Being a wartime helmet, however, the leather is extremely thin.
A close-up of the maker's mark "Lachmann Berlin" on top the skull interior.