Features: brand new and high quality Applicable for M42 lenses and most F-mount DSLR cameras Full manual control, manual for focus, manual exposure, aperture priority. for Infinity for focus is not available. Generally, the for focus of the 50 standard for head is about 2m, and the farthest for focus of the telephoto for head will be farther. M42 lenses without an A-M switch can also use this adapter after handling the aperture lever. This ring does not have an electronic chip and cannot for focus at for infinity. Specifications: Material:Aluminum Alloy Color:Black 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 Lens Adapter Ring