Product:Casing and Tubing Coupling, Casing Coupling, Tubing Coupling Application:Used for connect 2 joints of tubing or casing Size:Tubing Coupling : 1.9'' - 4-1/2'' Casing Couping : 4-1/2'' - 13-3/8'' Pipe Standard: API 5CT and 5B PSL1/PSL2 J55,K55,N80-1,N80-Q,API 5CT and 5B L80-1,C90, C95,T95, P110, Q125 Surface:Whole Phosphating or inside phosphating and outside coating Thread:NUE, EUE, STC, LTC, BTC etc.