Diamond Dry Vacuum Brazed Drilling Core Bits Set. Diameter: 6mm, 8mm, 10mm, 12mm, 16mm, 18mm, 20mm, 22m, 25mm, 28mm, 30mm, 32mm, 35mm, 68mm + adapter. Application: Used for opening holes in marble, ceramic tiles, granite, pebbles, walls and other materials.