Features: brand new and high quality Full manual control, manual for focus, manual exposure, aperture priority, for infinity for focus. for Infinity for focus, full camera, film machine available. M42-AI with the most precise workmanship, made of special metal material. Suitable for M42 screw lens adapter for Nikon AI and many other M42 mounts. The tightness and fit after transfer, the accuracy of focusing, the durability and firmness of each component, and the convenience of installation and disassembly are all the best. Specifications: Color: Black Material: Metal Appliaction: For M42 Note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1x Adapter Ring