150, 220, 320, 400, 600 Specialty Polishing Stone · Premium Aluminum Oxide · Soft Structure with Moderate to Fast Breakdown The PC (Polisher's Choice) finishing stone is made from premium select aluminum oxide grain, premium bond and a proprietary treatment process. It is a quick contouring finishing stone designed for rapid stock removal on tool steel, stainless steel and non-ferrous materials. The PC is engineered to be used as a final finishing stone on molds requiring a near mirror (diamond polished) finish and must be used by hand (check out our offering of Hand Holders!) with a lubricant. Try our Premium Stoning Oil or BORI-LUBE 10! Available in 150-1200 grit and a wide variety of sizes. Also available in regular and fine grit kits.