... five series, more than 500 types. They are Tapered Drilling Tools, Threaded Extension rod Main products:Tapered button bits (28mm ... 64mm,70mm,76mm,89mm,102mm,115mm, 127mm.)Down the hole drilling(drill bits, hammers, spare parts, drill tubes)Buttons type ... :Spherical, Ballisticrilling Tools, Downhole Tools, Tricone Drilling tools and Coal Mining Tools. We have our own special ...