United abrasives – sait 23306 depressed center wheel t1 5-1/2″x .045″ x 5/8-11″ ceramic alum. Oxide type 1 thin high speed cut-off 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. Fast cutting with extremely long life. Externally reinforced with fiberglass layers to provide ultimate safety in a thin wheel.