The DEWALT DWA8933 Extended Performance Ceramic Metal Grinding 9" x 1/4" x 5/8"-11 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. Diameter of 9", edge thickness of 1/4" and arbor size 5/8" - 11". Max RPM 6,600.