This is a Schneider-Kreuznach Xenar 50mm F2.8 prime lens with an M42 mount. ☆M42 mount. ☆This is a Xenar lens, not an Edixa-Xenar. The minimum focusing distance is 0.4m, and the M42 mount version was only manufactured for about two years, making this type of Xenar a very rare lens that is hard to find on the market. The Xenar 50/2.8 commonly seen on the market usually has a minimum focusing distance of 50cm. It produces beautiful bubble bokeh. The basic rendering is also good, and the "Schneider blue," where some colors have a bluish tint, was also confirmed with this lens. ◯Regarding the exterior, there are paint剥がれ and minor scratches due to use, but there are no major scratches or damage that would cause problems with use. ◎Regarding the optics, there is no clouding or mold that would affect the image quality, and I was able to take pictures comfortably. The coating is also in perfect condition. ⇛I believe it is in good condition. ☆Due to the unique mechanism of this lens, many units seem to have problems with the operation of the aperture, etc., but this unit has smooth operation of both the aperture ring and the focusing ring. Operation is smooth.