Down Hole Tools, Cementing Tools, Wellhead Equipment manufacturer / supplier in China, offering API7-1 Spiral Drill Collar Non Magnetic Drill Collar for Oilfield, API 7-1 Oilfield Spiral Drill Collar/P550 P530 Non Magnetic Drill Collar, API 11b Polished Rod and Spray Metal Polished Rod for Oilfield and so on.