Drill Pipe, Drill Rod, Diamond Bit manufacturer / supplier in China, offering 57.2-117.5mm Head Assembly 1.81-4.06 Inch Nq Bq Hq Pq, Customizable Designs Reliable Bit Performance High Diamond Volume Percentage PDC Drill Bit, Casing Shoe Bit for Geological Core Drilling Aw, Bw, Nw, Hw, Pw and so on.