Shanghai Jingoo petroleum apparatus Co., Ltd was founded in 2003. We are specialized in API SPEC 5B , SPEC 7 series thread gauge exporting. We are the sole API thread gauge export agent of Baoji Oilfield Machinery Co., Ltd, Chengdu Chengliang Tools Group Co., Ltd and Shaan Xi Aviation Hongfeng Precision Mechanical Tool Corporation. They are the three unique factories with API SPEC 5B, SPEC 7 Certificate of thread gages in China. All of our export products provided independent third-party certification which is recognized by API. Based on professional and honesty, we welcome the worldwide partners.