Aiskaer 60mm Diamond Hole Saw Drill Bit Set - Diamond Hole SAW Drill BIT FOR Ceramic, Porcelain Tiles, Glass, Marble, Granite Made of high-strength steel and high-quality corundum powder, and fine workmanship; durable, high precision machining, smooth appearance, heavy quality This diamond coated core drill bit removes a complete circle from glass, tiles, marble, granite, cer Easy to use, high quality,good performance, long life - Excellent for making clean and accurate hole Always use lubrication (water ), otherwise the diamond core drill will burn - Start your hole diagon Start your hole diagonally, make a round trace and then hold drill straight.