First stage after belt grinder when making knives. With black compound, use to take out scratches and align grinding marks . Can be used to get final satin finish prior to coating or etching a blade. Approximately 400 grit finish. I use 3 more descending grit airway wheels and buffing compounds to get non-coated blades to various satin finishes or to a final mirror finish, without hand sanding. These treated airway wheels, used properly, are a game changer in metal finishing. But! They are aggressive and the buffer is the most dangerous machine in any shop. Use safely glasses, mask, hearing protection, and a heavy apron. Hold your item firmly with both hands. These are not the buffing wheels you are used to. They will “grab” your item before you know it, and deliver it back to you like an arrow. Properly used, this is a great product!