DEWALT DWA8906 Extended Performance Pipeline Grinding 4-1/2" x 1/8" x 7/8" Ceramic Abrasive is designed with premium ceramic grain for fastest material removal and longest life of the DEWALT bonded abrasives. This ceramic abrasive is designed for metal and stainless steel grinding and cutting. Diameter of 4-1/2", edge thickness of 1/8" and arbor size 7/8". Max RPM 13,300.