This is an exact reproduction of the cone nut produced by Mercury. WE WILL NOT BE MAKING ANY MORE. An Oillite bushing is used in stead of the later style with needle bearing as used on the Mark 20H and later engines. The nut is T-6 6061 marine grade aluminium. We have sold many of these but be careful they are only usable in the gear case meant to accomadate this style which has a shorter thread depth.