MTP Pack of 10 4.5" x 7/8" 40 Grit Zirconia Flap Disc Grinding Sanding Wheels T29 #40 Pack of 10 4.5" x 7/8" Zirconia Flap Discs Disc Size: 4.5" Arbor size : 7/8" Material: Premium Grade Zirconia Type : T29 Reinforced Fiberglass Backing Max Operating rpm: 13,300 Use for Metal , Stainless Steel Meet ISO 9001 Standard