DEWALT DW4551 Masonry Grinding Wheel, 5/8-11-Inch Arbor, 4-1/2-Inch by 1/4-Inch 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