This is a 62mm adapter ring, for use with the Nikon AF-4 filter holder.
Urth 86-62mm Adapter Ring for 100mm Square Filter Holder
Nikon 72mm Adapter Ring for AF-4
Nikon 67mm Adapter Ring for AF-3
Nikon 52mm Adapter Ring for AF-4
Nikon 77mm Adapter Ring for AF-4
JJC Nikon Fit Reversing Ring 62mm
