Flap Disc, Blue Zirconia, 36 Grit Type 27, Depressed Center, 4-1/2" with 7/8" Arbor ZA36, for right angle grinders. Cuts fast and outlast sanding discs 10-to-1. Multiple layers of zirconia cloth flaps constantly exposing new extra sharp grinding points. Laminated by state-of-the-art automated equipment. Reinforced fiberglass backing plate. Each disc balance tested for vibration-free grinding/finishing. Wheel Size: 4-1/2" Arbor: 7/8" Grit: 36 Spec: ZA36 Max RPM: 13,300 Tool Type: Right Angle Grinder