Genuine Diablo replacement part. 4-1/2 in. Metal Dual Cut & Grind Disc - Type 27. Premium Aluminum Oxide Blend - a superior quality formulation designed for fast material removal and long grinding life. Dual Cutting and Grinding Application - a first of its kind, this disc allows you to cut and grind simulataneouly. For use on metal applications: steel, stainless, cast iron, sheet metal.