Diameter: 25mm / 0.99"Packing included: 1 x diamont drill100% brand new and high qualityTile glass ceramic marble porcelain drillingDiamond dust saws are suitable for drilling ceramic tile, glass, marble, slate and porcelain tiles up to hardness grade 5For use with conventional electric drills on lower speed settings has the hammer deactivated actionAlways use lubrication (water), otherwise the diamond drill core will burnCooling and lubricationWhen cutting hard materials, it is important to ensure Auger is preserved at the expense to avoid damaging the material bore and a cup premature wear.The use of water as coolant / lubricant prolongs the service life of these saws.If you are drilling on a vertical surface try hand spray water or sponge wet water and kept below, but in contact with the wick.Keep the little wet as possible during operation, if the bit dry during use, it could overheat and immediately dull.Note:Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3 cm.