New 1 piece of 100mm 4" diamond coated grinding disc / wheel. The size is 100mm outside diameter. Bowl shape wheel for ease of grinding. the hole in the middle is 16mm diameter 2mm thickness, grit 100, RPM 12000. | Suitable for use in grinding on glass, marble or rock. US-BASED CUSTOMER SERVICE: Available by chat, email, phone, or visit us at our customer service center in La Crosse, WI.