These Bosch Diamond Drill Bits are specifically engineered for accurate dry drilling in porcelain and natural stone tile, for a precise, clean hole. Each bit features a built-in wax insert inside the tip, which lubricates and cools the hole, which means you don't have to use water like other diamond bits. Drilling without water allows two hands to guide the tool, for more accuracy. We use a special vacuum brazing technology to fuse the high-quality diamonds to the bit tip, for longer bit life than electroplating, for 10x longer life in porcelain than standard glass and tile bits. These bits are ideal for installing bathroom accessories, such as towel bars, mirrors, shelves, grab bars, paper roll holders and more.