Professional Diamond Hole Punch: with special brazed diamond design for porcelain, glass, marble, ceramic, stone and granite, etc. High Quality Hole Drilling: Made of carbon steel with diamond blade, ideal for drilling clean, precise holes and cutting perfect circles with these tools Long Life: Heavy duty hole saws offer superior performance and more than 8 times durability Tips: The electroplated diamond coating will wear off if the tool gets too hot, never let your drill dry out Package Included: 6mm, 8mm, 10mm, 12mm, 16mm, 20mm, 22mm, 25mm, 30mm, 38mm, 50mm. 11Pcs Drill Bit Set Product Description Specifications: Material: Carbon Steel 11Pcs 6mm-50mm Diamond Hole Saw Drill Bit Set Features: This diamond coated core drill bit removes a complete circle from glass, tile, marble, granite, ceramic or other materials p> Note: If you feel the burning, take a step back! Either your speed is too fast or the pressure you are applying is too much. They should never feel hot to the touch, even