United abrasives – sait 22264 depressed center wheel t27 4-1/2″x 1/8″ x 7/8″ ceramic alum. Oxide type 27 cutting/grinding wheel, ceramic aluminum oxide grain. High performance, very uniform, high density grain structure is extremely durable and self sharpening for long life and cooler cut. Long life combined with versatility for the pipeline industry. Reinforced with the highest quality fiberglass for maximum safety and performance