12 1/4" 311mm T. C. I. Tricone Bit for Oil Drilling IADC 517g
China 12 1/4" 311mm T. C. I. Tricone Bit for Oil Drilling IADC 517g, Find details about China Tri-Cone Bit, API Certification from 12 1/4" 311mm T. C. I. Tricone Bit for Oil Drilling IADC 517g