12 1/4" 311mm T. C. I. Tricone Bit Three Cones Bit for Oil Drilling China API

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