All rings have the same outer diameter and will work with most follow focus systems (standard 32 pitch - 0.8 mod). Each focus ring are adjustable and fit 65mm, 75mm, and 85mm lenses. Includes a 1-year warranty and U.S.-based support. Made with hard plastic, the lens rings can endure the rigorous turning and adjusting without breaking easily. These lens rings feature a large pitch diameter so you can accurately focus your subjects clearly and in-frame with ease.