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 and 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 All discs feature patented, Ceramic Alumina abrasive and a unique, fiber reinforced backing. The 3X Ceramic Alumni Grain is a high performance disc that fits five- and eight-hole sanders and lasts three times longer than conventional aluminum oxide discs, is edge tear resistant, and provides a consistent finish. The hook-and-loop backing provides an easy change option.