Moore's Brass Center Discs have been the industry standard since 1898. They snap on and off quickly and easily, with no screws to drop or lose. Moore's discs can be used with the grit side in or out and won't come off with the reversal of the handpiece. Moore's Discs are available in paper, waterproof, adalox and MoorPlastic, in four sizes: 1/2", 5/8", 3/4" and 7/8".