EC Moore's Brass Center Discs have been the industry standard since 1898. Moore's discs can be used with the grit side in or out and won't fall off with the reversal of the handpiece. Brass center, aluminum oxide. Mounted on thin backing, provides excellent results in sanding and smoothing operations. The flexible backing allows accessibility to hard-to-reach areas. Sold 12 boxes of 50 discs per box.