Forney blue zirconia flap discs cut fast and outlast sanding discs 10-to-1. This disc also offers great flexibility. It's the ideal abrasive disc for rough or fine finishing. The multiple layers of zirconia cloth flaps constantly expose new extra sharp grinding points for extended product life. Laminated by state-of-the-art automated equipment. Reinforced fiberglass backing plate. Each disc is balance tested for vibration-free grinding/finishing. Type 29 wheels are excellent for grinding and finishing applications. Designed to be used on Right angle grinders.