Grinding wheel. 7/8 arbor. 4-1/2″ x 1/4″ diameter. 30 grit, aluminum oxide grain. Aluminum oxide grain. Max. RPM 13,280. Small angle grinder. Designed for use with small angle grinders. Type 27 depressed center wheel for grinding. For use on flat surfaces for weld preparation. Best used at a 30-degree angle. Aluminium oxide special grain cuts high-tensile strength materials without excessive fracturing. Not to exceed 10,200 RPM.