Norton 3X discs are manufactured with a blend of ceramic alumina and heat-treated aluminum oxide grain that cuts fast yet remains cool. They last longer due to the unique resin bonding system that secures the abrasive to the fiber reinforced backing and an anti-clog coating is applied. The 5-inches discs can be used on any random orbit sander due to the patented universal vacuum hole pattern. Patented, ceramic alumina abrasive, P-graded (80-320) lasts 3X longer than conventional aluminum oxide abrasive. Superior cut rate with consistent finish. Unique, fiber reinforced backing makes the edge tear resistant. Non-pigmented, waterbased zinc stearate (anti-clog), open coat for reduced loading and no finish contamination. Patented, universal vac hole pattern fits 5 and 8 hole vac sanders. Hook and loop backing for quick and easy disc change, allows repeated use until disc is worn. Fine for finish sanding and cleaning of bare surfaces.