N/a manufacturer / supplier in China, offering API 7-1 3 1/4" Diamond PDC Drill Bit for Water/Oilfield/Gas Well Drilling, API 12 1/2inch IADC437 Mining Rotary Roller Cone Tricone Drill Bit for Oil&Water Well Drilling, API 12 1/4inch IADC437 Mining Rotary Roller Cone Tricone Drill Bit for Oil&Water Well Drilling and so on.