These came out of a salesman sample lot, and contain many types. These are Spedecut Abrasives Speedlok Discs, 2" and 3", and corresponding holder pads, which would then insert into your drill or tool for use. You put the disc on the holder, apply a little pressure and it screws onto the holder via the RUBBER center of the disc. I don't believe these are made anymore, but sure would be handy. I'm not certain, but I think they were primarily for use on metals. Please examine all photos for the sizes and types. All are new, one package is missing one piece. Most packages have 5 pieces each. A total of 31 pieces. Please examine all photos. NO international shipping. Thank you for your interest.