The DEWALT DWA8280H 4-1/2" x 5/8"-11 40G T29 XP Ceramic Flap Disc is designed with Premium XP Ceramic Cloth for long life and fast material removal. These flap discs are intended for surface prep grinding, along with grinding and blending welds. The ceramic flap disc allows you the ability to grind flat on materials with a finish of a fiber disc. These discs perform 50% faster than standard flap discs (50% faster vs XP) and provides 2.5X longer life than the standard flap disc. 40 Grit.