N/a manufacturer / supplier in China, offering 12 1/4" (311.1mm) IADC637g Tricone Drill Bit, Tricone Rock Bit, TCI Tricone Bit, Mining Well PDC Drilling Bits 17-1/2 Inch API 7-1 Standard Factory Drill Bit Steel Body PDC Bits, API IADC517 8 1/2" TCI Drill Bit for Well Drilling and so on.