Drill bit sizes: 6mm, 8mm, 10mm, 12mm Vacuum hot sintered for maximum strength and reliablilty M14 attachment for use with angle grinders or powered drill using an adaptor kit (sold separately) Suitable for dry or wet use (wet use will increase working life) Designed to generate less heat which improves reliability and reduces the chance of chips, cracks and breaks Cooling significantly extends reliability. For solid hole drills (diameters less than 20mm) use Smith Tools Cooling Resin (purchased separately) , for diameters larger than 20mm we recommend continuous water spraying or frequent immersion of the bit in cold water Supplied in a hard-wearing reinforced aluminium case Recommended for use with porcelain, stoneware, hard ceramics, granite, marbe, quartz and other natural stones