... precision grinding sharp, high, the advantages of small noise, and the holes do not produce the tremor, clean, smooth, ... to work in cooling water.1.Feature: durable to polish and not crack, high efficiency, long life, drill 4000-5000 ... Europe market.3. Application: glass, Ceramics,cameo, stone, agate, sheel, tile and other hard materials4.Complete specification: Straight shank, Taper shank ,thread ...