... tubing coupling Std Ref:API 5CT and 5B Grade:J55,K55,N80,L80,C90,P110, N80-1,N80-Q Type ... : 1.9-4-1/2 Threads:NU, EU Coupling Manufacturer of Tubing and Casing coupling according ... Q, L80, C90, P110 2.We also supply permium thread products by customer's request 3.Size: tubing coupling ... /8" 4.Type: NU, EU(tubing coupling), STC,LC,BTC(casing coupling). 5.Surface treatment: Whole phosphating, or ...