Copy (electrotype) in Römische-Germanisches Zentralmuseum, Mainz.
The copy appears to have had a crest knob added, although for this model this should not be the case. Alternatively, it may simply be the angle from which the photograph is taken and the crest knob is attached to the helmet behind, which is otherwise invisible.
References:
Robinson, H.R. (1975), "The Armour of Imperial Rome", (Arms & Armour Press), p.28-9, No.43
