... : API 5CT Tubing Coupling J55 2.Grade: J55,K55,N80,L80,P110 3.Thread:EUE,NUE api 2 3 8 j55 k55 tubing coupling ... coupling from 1.9” to 4-1/2”, Casing coupling from 4-1/2” to 13-3/8”TYPE: NUE, EUE (tubing coupling ... by requirements of customers------------------------------------------------------------------------------- API 5CT Tubing Coupling J55 api 2 3 8 j55 k55 tubing coupling