12 1/4" 311mm Milled Tooth Tricone Bit for Oil Drilling IADC 127
China 12 1/4" 311mm Milled Tooth Tricone Bit for Oil Drilling IADC 127, Find details about China Tri-Cone Bit, API Certification from 12 1/4" 311mm Milled Tooth Tricone Bit for Oil Drilling IADC 127