3pcs Vacuum Welded Drilling Bits M14 Thread Diameter Diameter 6,8,10mm, Total Length 60mm, M14 Thread Dry or Wet Drilling Tile, stone, marble, granite, ceramic Vacuum brazing technology provides much longer life than galvanized ones Less chipping; Minimize breakage; Less heat generation; Best Finishing Quality Product Description Cooling Wax The inside of the drill bit is filled with dense cooling wax to cool diamond drill bits and extend the life of drill bits. Application Drilling porcelain, tile, marble, brick, stones, granite, masonry and all similar materials not recommended for material behind tile. Use When building/refitting a bathroom or kitchen, such as installing a shower or installing a faucet and handles in the bathroom, you need to drill holes through the porcelain tiles without cracking them. So you can use our diamond tipped drill bit to make those holes very precisely.