Nikkor-N.C 5cm f1.1 S Mount Rangefinder Lens (read)
This is a RARE lens. I can only find a couple of mentions of it online and none for sale. This lens has a lot of fine scratches on the front. Also, there are no aperture blades so you can only shoot wide open. Cosmetically, the lens looks quite good. It comes with the front cap (no rear) in the unusual tapered case.