Depressed center wheels may also be referred to as raised hub wheels or by their shape designation of ''Type'', with Type 27 being the most popular. The depressed center design allows the flange/lock nut to recess within the wheel so that it can be used for various grinding and cutting applications. Depressed center wheels are designed to handle the most severe right angle grinding applications from heavy stock removal to rough blending. Proprietary ceramic aluminum oxide shaped grain with advanced bond system provides greater performance up to 10 times of aluminum oxide wheels.