The Vevor flap disc set includes 10 industrial-grade zirconia sanding discs designed for angle grinders. These Type 29 discs are built for grinding, deburring, rust removal, sanding, and surface finishing on metal, wood, stone, and concrete. The 60 grit abrasive provides efficient material removal with a smoother finish. With a 4-1/2" disc diameter and 7/8" arbor, they fit many common 4-1/2" and 5" angle grinders. The durable resin fiber and fiberglass backing help provide long-lasting performance under demanding use.