DEWALT DW8325 7-Inch by 7/8-Inch 120 Grit Zirconia Angle Grinder Flap Disc Zirconia grit enables 3X faster material removal than fiber resin metal sanding discs Premium abrasive cloth provides up to 15 X longer life than fiber resin metal sanding discs Type 29 fiberglass backing provides grinding angle of 20-25 degrees Zirconia grit enables 3X's faster material removal than fiber resin metal sanding discs Premium abrasive cloth provides up to 15X's longer life than fiber resin metal sanding discs Type 29 fiberglass backing provides grinding angle of 20-25 degrees