Name:tubing couplings Std Ref:API 5CT Grade:J55,K55,N80,L80,C90,P110, N80-1,N80-Q Type: NU, EU ... Coupling Manufacturer of Tubing and Casing coupling according to API ... customer's request 3.Size: tubing coupling from 1.9" to 4-1/2",Casing coupling fro4-1/2"to 13-3/8" ... 4.Type: NU, EU(tubing coupling), STC ...