Nikon EL-NIKKOR 50mm f/2.8N Enlarging lens. The size section says F-mount, but it is actually L39. I was using it on an enlarger until recently. The exterior is generally clean. There is some dust and mold inside the lens due to age and use, but it did not affect the image quality. Please make your judgment based on the photos. This is an old item, so no claims and no returns, please.