Management Number E41 This is a Contax C mount, not a Nikon F mount. I selected that option as there was no other choice. A very rare lens has arrived. The Nikkor-P.C 10.5cm f/2.5 (Contax C mount version) early model is extremely rare and appears on the market less often than the Nikon S mount version, making it a valuable item. Below is a detailed explanation of the reasons and background. In 1953, Nikon manufactured lenses not only for its own Nikon S mount rangefinder cameras but also for the Contax C mount. However, because the Contax system itself was in competition with Carl Zeiss in West Germany, Nikon's opportunities to supply lenses for Contax were limited. Therefore, the production volume of Nikkor lenses for the Contax C mount was generally low. As a symbol of Japan's proud optical technology after the war, this lens was trusted by professional photographers worldwide. With an optical design by the legendary designer "Teiya Iwabuchi," you can enjoy a rendering that cannot be experienced with modern lenses. Comparison with the S mount version: The Nikon S mount version was widely sold for Nikon's own cameras (Nikon S series) and had a large production volume, so it can still be found relatively often today. On the other hand, the Contax version had a limited market, resulting in a smaller production volume and, consequently, less circulation. And the most significant point is that this is an early model. It is far more valuable than the later models. A serial number in the 8,000,000 range indicates an early model, and the "red 'C'" specifically denotes coating, signifying an early model. In conclusion, the Contax C mount version of the Nikkor-P.C 10.5cm f/2.5 is undoubtedly rarer than the Nikon S mount version, and Nikkor lenses for the Contax C mount are particularly highly regarded among vintage camera enthusiasts and collectors in Europe and America. This is undoubtedly a must-have item for collectors. Regarding its condition, it is in very good condition. No mold or fog was observed. There are some minor scratches, but I judge them to be of no particular concern. There is some oil staining on the aperture blades, but it does not affect their opening and closing at all. The exterior has some minor scratches. Please refer to the photos. Operation has been confirmed. There are no issues.