The DeWalt DW4557 is a 9 x 1/4 x 7/8-Inch General Purpose Masonry Grinding Wheel. Features: Silicon carbide grain for long wheel life in all masonry materials High grain concentration for aggressive grinding action and smoother running wheels Proprietary wheel design ensures durable long life wheels 3 full sheets of glass in every 1/4-inch wheel and 2 full sheets in every 1/8-inchwheel for added durability and safety What"s In the Box: DeWalt DW4557 9 x 1/4 x 7/8-Inch General Purpose Masonry Grinding Wheel