Name:tubing couplings Std Ref:API 5CT Grade:J55,K55,N80,L80,C90,P110, N80-1, ... , EU Coupling Manufacturer of Tubing and Casing coupling according to API SPEC 5CT AND 5BAPI couplings for oil tubing and casingSize ... , anchors of oil pumps and revolving sand gravitated device, etc API 5CT oil tubing couplings