Unique wave design allows easier hole entrance and smoother cutting * Can be used on granite and marble. The 3/16 PORC+ bit provides a great pilot hole for the Diamond Hole Saw and is included. For use on all types of porcelain tile up to a scratch hardness of 8The 3/16? PORC+ bit provides a great pilot hole for the Diamond Hole Saw and is includedFor best results, cut holes at 400 to 600 RPMs using a liquid coolant