Dewalt DW8313 Specifications:Diameter 4-1/2"Arbor 5/8"-11Grit 80Dewalt DW8313 Features: 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 optimal grinding angle of 10-25 degrees, allows full use of the disc, and won't mar the work piece