Norton ProSand MULTI-AIR 5" Multi-Hole Pattern Hook & Sand Disc, 50 pack - 320 Grit Resin bonded aluminum oxide abrasive is coated on a durable Xwt backing to provide maximum life. Free cutting and clog resistant open coating makes cloth discs ideal for heavy stock removal Hook & Loop discs can be used on portable random orbital sanders Norton cloth sanding discs are made with aluminum oxide abrasive for long life The heavy, X-weight cotton backing makes them durable