API Spec 7-1 Oil Drilling Drill Collar Lifting Sub 3 1/2"- Nc31 AISI 4145h Hebei Shitan Machinery Manufacturing Co., Ltd. API Spec 7-1 Oil/Gas/Water Drilling Lifting Sub 3 1/2"- Nc31 AISI 4145h Hebei Shitan Machinery Manufacturing Co., Ltd. API Spec 7-1 Oil/Gas/Water Drilling Drill Collar Lifting Sub 3 1/2"- Nc31 AISI 4145h Hebei Shitan Machinery Manufacturing Co., Ltd. API Spec 7-1 Water Well Drilling Lifting Sub 3 1/2"- Nc31 Hebei Shitan Machinery Manufacturing Co., Ltd. API Spec 7-1 Water Well Drilling Drill Collar Lifting Sub 3 1/2"- Nc31 Hebei Shitan Machinery Manufacturing Co., Ltd. API Spec 7-1 Gas Drilling Drill Collar Lifting Sub 3 1/2"- Nc31 Hebei Shitan Machinery Manufacturing Co., Ltd. API Spec 7-1 Oil Drilling Drill Collar Lifting Sub 3 1/2"- Nc31 Hebei Shitan Machinery Manufacturing Co., Ltd. API Spec 7-1 Oil/Gas/Water Drilling Drill Collar Lifting Sub 3 1/2"- Nc31 Hebei Shitan Machinery Manufacturing Co., Ltd. API Spec 7-1 Water Well Drilling Lifting Sub 2 7/8"- Nc26 AISI 4145h Hebei Shitan Machinery Manufacturing Co., Ltd. API Spec 7-1 Water Well Drilling Drill Collar Lifting Sub 2 7/8"- Nc26 AISI 4145h Hebei Shitan Machinery Manufacturing Co., Ltd. <<<1213141516>>>
