Professional Type Vacuum brazed (VB) diamond drill bits are professionally produced for wet or dry drilling in all types of ceramic, porcelain, tiles, granite, marble, stoneware, and other hard materials. Thanks to VB technology, the diamond drill bits can drill dry or wet on hard porcelain and stone with greater efficiency and longer service life. Diamond drill bits with M14 thread connection can be used directly on the angle grinder. Easy operation, applied for DRY and WET drilling, can work in all conditions. The perfect tools are at your fingertips. Diamond drill bit allows you to drill the holes needed for water inlets, drains, light points... Diamond drill bit can dry drill dozens of holes in HARD PORCELAIN, much longer life than electroplated (almost 10 times). You can drill many more holes wet. To make diamond drill bits last longer, please follow the correct instructions for use.