New Ushio #71818 Nikon Profile Comparator Lamp or new Nikon stamped original version of the lamp.  The specifications on this lamp are as follows:

It is a 10 volt 70 watt  incandescent  lamp.  Limited quantities.  Replacement bulbs now list for $119 each.

It fits the ZA Comparator (Surface) Nikon , 3 Comparator (Surface) Nikon , 3A Comparator (Surface) Nikon, 6C Shadowgraph Profile Projector Nikon, Comparator 2A (Surface) Nikon, Comparator 3 (Surface) Nikon, Comparator 3A (Surface) Nikon, Comparator 6C (Shadow/Surface) Nikon, Mitutoyo, Mitutoyo PJ250B, Nikon, Nikon 6C Shadowgraph, Nikon C6 Shadowgraph, Nikon Comparator 2A (Surface), Nikon Comparator 3 (Surface), Nikon Comparator 3A (Surface), Nikon Comparator 6C (Shadow/Surface), Nikon Comparator 6C Hi-Intensity, PJ250B Mitutoyo, Shadowgraph 6C Nikon, Shadowgraph C6 Nikoneiss