DEWALT DW8359 4-1/2-Inch by 5/8-Inch-11 120g Type 27 HP Flap Disc 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 27 fiberglass backing provides grinding angle of 5-15 degrees