API Spec 7-1 AISI 4145h Oil/Gas/Water Drilling Drill Collar Lifting Sub 73mm- Nc23 Hebei Shitan Machinery Manufacturing Co., Ltd. API Spec 7-1 Water Well Drilling Lifting Sub 5"- 7 5/8 Reg AISI 4145h Hebei Shitan Machinery Manufacturing Co., Ltd. API Spec 7-1 Water Well Drilling Drill Collar Lifting Sub 5"- 7 5/8 Reg AISI 4145h Hebei Shitan Machinery Manufacturing Co., Ltd. API Spec 7-1 Gas Drilling Lifting Sub 5"- 7 5/8 Reg AISI 4145h Hebei Shitan Machinery Manufacturing Co., Ltd. API Spec 7-1 Gas Drilling Drill Collar Lifting Sub 5"- 7 5/8 Reg AISI 4145h Hebei Shitan Machinery Manufacturing Co., Ltd. API Spec 7-1 Oil Drilling Lifting Sub 5"- 7 5/8 Reg AISI 4145h Hebei Shitan Machinery Manufacturing Co., Ltd. API Spec 7-1 Oil Drilling Drill Collar Lifting Sub 5"- 7 5/8 Reg AISI 4145h Hebei Shitan Machinery Manufacturing Co., Ltd. API Spec 7-1 Oil/Gas/Water Drilling Lifting Sub 5"- 7 5/8 Reg AISI 4145h Hebei Shitan Machinery Manufacturing Co., Ltd. API Spec 7-1 Oil/Gas/Water Drilling Drill Collar Lifting Sub 5"- 7 5/8 Reg AISI 4145h Hebei Shitan Machinery Manufacturing Co., Ltd. API Spec 7-1 Water Well Drilling Lifting Sub 5"- 7 5/8 Reg Hebei Shitan Machinery Manufacturing Co., Ltd. <<<23456>>>