... L-80 .N-80,J-55 and K-55 P-110 2.Casing joining coupling and tubing coupling 3.STC.LTC.BTC ,Premuin ... 10 years experience of producing ,developing and selling oil pipes and their accessories, steel pipe fittings and other down well toolsOur company manufactures ... , adapter pup-joints, adapter couplings, stabilizers, anchors of oil pumps and revolving sand gravitated device of well, etc. We always do ...