Ideal for cutting, sawing, carving, sharpening, and filing hard materials including marble, concrete, brick, porcelain, ceramics, epoxy, and hard woods. Wheel is completely coated with fine diamond particles for working with hard materials. designed to last and not loose its shape or break, it provides smooth fine cuts. Bit diameter: 7/8", shank diameter: 1/8", thickness: .023". Includes mandrel model No. 402.