This is an item for business contractors. This product is especially effective for processing that requires precision using a precision cutting machine with an extra level of precision. The diamond whetstone has excellent processing of hard, brittlelele-resistant materials for a long life. Compatible Material Examples: Ceramics, Hard Glass, Quartz, Crystal. Outer Diameter: 7.1 inches (180 mm); Thickness: 0.02 inches (0.6 mm); Inner Diameter: 1.0 inches (25.4 mm).