Drill Bit, TCI Tricone Bit, PDC Bit manufacturer / supplier in China, offering 8 1/2 Inch IADC 637 Single Roller Cone Bits/TCI Roller Cone Cutters, Solid Drilling Machine Rock Hole Opener with TCI Roller Cone, API 7-1 IADC 537 Tungsten Carbide Insert Drill Bits and so on.