CGW Abrasive Flap Disc works excellent on carbon and stainless steel. CGW 4 1/2 Regular 27 Depressed center ZA flap disc offers high stock removal and extended service life. Disc having an arbor size of 7/8 and grit size of 40 is tough and aggressive for a low noise no vibration action. • Grit/Grade: 40 (medium). • Diameter: 4 1/2-inch. • Backing material: Polyester/Cotton. • Abrasive material: Z3 -100% zirconia alumina. • Applications: Deburring deflashing rust removal snagging. • Applicable materials: Ferrous and non-ferrous metals stainless steel high tensile alloys woods plastics. • Used with: Right angle grinder/sander. • Contaminate-free for working on flat grinding surfaces most efficient when used between 0 deg - 15 deg angle the best choice for smooth finishing. • Recommended for aggressive use and heavy duty applications. • Made in USA. • Sold as 1 Each.