This is a Nikkor 50mm f1.4 (Ai-s) fast, prime, manual lens for Nikon cameras, which comes with a Canon adapter, UV filter, step-up ring, and Promaster/Canon caps. The lens - serial # 5299390 - has a fixed focal length of 50mm and a maximum aperture of f/1.4, making it ideal for low-light photography and creating a shallow depth of field. It is solidly made of aluminum and glass. The lens is compatible with 52mm filters and has a Nikon F mount. This lens makes gorgeous pictures! Google it online to check reviews. Please look at the photos and judge the cleanliness of the glass for yourself. The bonus step-up ring is there to support the Promaster front cap. If you prefer, you can remove the step-up ring, the Tiffen UV protector and the Canon adaptor. All the items you see here are included. Shipped carefully wrapped within 2 days of receipt of funds.