professional diamond crown with M14 thread - for angle grinders for "dry" precise and fast drilling in stone, tiles, tiles, granite, marble and other extremely hard materials not only in the construction industry diamond layer height 10 mm, long lifetime without the need to use any additional tools, you can cut the exact hole in the desired location recommended working procedure - screw the crown directly onto the thread of the angle grinder head, tighten firmly, begin cutting the desired hole at an angle of 45°, the crown and the speed of the grinder immediately ensure the fit in the desired location, slowly, with evenly generated pressure, straighten the alignment direction to the vertical position, Smaller diameters of 6 - 14 mm are for drilling in hard tiles. Between drilling COLD - just immerse in a glass of water or let cool in the air. Instructional video