heavy-duty 4-1/2 x 1/4-inch metal grinding wheel takes care of the toughest grinding jobs with its high performance aluminum oxide grain and three-sheet fiberglass construction. Its aggressive grain concentration (A24R grit) allows for these grinding wheels to handle heavy-duty grinding of ferrous metals (steel, iron welds, edges), weld blends, stainless steel, and hard alloys. DEWALT uses a proprietary material in these grinding wheels to ensure long life and consistent performance. This package includes five grinding wheels.