Canon Control Ring Mount Adapter EF-EOS RThe Canon Control Ring Mount Adapter EF EOS R lets you mount Canon EF and EF S lenses to EOS R mount cameras but it also adds a programmable Control Ring, like you'd find on native EOS R lenses. You can set it to do almost anything: control aperture, adjust ISO, destroy objects with your mind no you can not. But it's in excellent condition, with only very minor cosmetic wear.