JoolTool 3M Scotch-Brite Unitized Abrasive Disc, Non Woven Web Backing, Aluminum oxide, 3S Fine Grade, 3" Diameter An excellent choice in jewelry repair work for its ability to wipe off scratches and scuff marks on precious metals It is great for removing porosity and parting lines in jewelry castings The material consists of aluminum oxide impregnated in a non woven web, which resists loading and has an extremely long life Fine grade Size: 3" diameter