4.5” x .25" x 5/8”-11 Grinding Wheel with Hub by Black Hawk Abrasives are 4-1/2 inch diameter aluminum oxide bonded abrasive wheels designed for medium to heavy stock removal grinding. Each 4.5 inch grinding stone starts with the internal reinforcement of high tensile strength fiberglass mesh. The grinder discs comes together with premium A24T aluminum oxide grains, providing increased hardness. The increased hardness makes the wheel grind away material quicker without sacrificing the abrasive of the wheel itself meaning it can take a beating even during the toughest jobs. Meant to be attached to a 4.5" angle grinder, this 4.5” grinding disk is the perfect abrasive wheel for general grinding, rust removal, removing weld splatter or even rust removal. Use this 4-1/2” x 1/4" x 5/8”-11 hubbed grinding rock on steel, structural steel, all ferrous metals, iron pipe, metal tubing or bar stock. Additionally, this 4.5 inch grinder wheels come with an easy screw on hub attachment. The hub eliminates the need for a flange attachment that the non-hub grinding wheels require.