Master Mechanic 4-1/2" x 1/4" x 5/8"-11 Masonry Grinding Wheel with Metal Hub is for grinding and deburring metal or masonryUse with 4-1/2" angle grinders and has a maximum RPM of 13,200. This grinding wheel is made of high-quality materials that are durable and long-lasting. It is also easy to use and can be quickly and easily attached to an angle grinder.