Brass step-up ring resistant to deformation and distortion This step-up ring is made of brass, which is resistant to deformation and distortion, reducing thread jamming and wobbling. The wider pitch of the knurling allows for a firm grip, making the ring easy to attach and detach. The lens mounting surface is treated with felt to prevent reflections. I have used it about 5 times, but I am selling it because I have replaced my lenses and no longer have the opportunity to use it. It is in beautiful condition, but it has been stored at home. If you are sensitive or do not understand used items, please request photos of any areas of concern before purchasing, or consider purchasing after reviewing the photos.