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 Specifications Speed: 13,000 Size: 7/8" arbor PKS: 10 Diameter: 4-1/2" Quantity: 1 Application: Manuf # : DW8308 Type: Z60 grit