The Strend Pro diamond router bit is designed for enlarging, finishing, and chamfering existing holes in hard tiles, ceramics, porcelain stoneware, glass, and marble. It is not designed for drilling new holes. Finished holes reduce the risk of subsequent cracking of tiles, glass, or marble. We recommend routing up and down to utilize the full height of the router bit, helping to keep it cool. It is used for dry routing on an angle grinder (M14 thread).