CGW Coated Sanding Disc, 1/2 in Diameter Head, 1 in Length of Cut, 2-3/4 in Overall Length, Cylindrical - With End Cut Shape SB Head Shape, Double Cut Cut, 1/4 in Shank Diameter, Carbide Head, 38000 rpm Maximum, Applicable Materials: Cast Iron, Copper, Ferrous Metals, Fiberglass, Hard Rubber, Iron Alloys, Plastic, Nickel, Stainless Steel and Titanium, Industry Specification: SB-5.