DEWALT DW4759 7-Inch by 1/4-Inch by 5/8-Inch-11 Concrete/Masonry Grinding Wheel This are easy to use This are highly durable This is manufactured in China Silicon carbide grain for long wheel life in all masonry materials High grain concentration for agressive 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