tubing coupling and casing coupling

Product Details Place of Origin: China Certification: API Thickness: 4, 20 Application: Oil Pipe Technique: Hot Rolled Alloy Or Not: Non-alloy Secondary Or Not: Non-secondary Special Pipe: API Pipe Section Shape: Round Outer Diameter: 60, 508 1.Size: tubing coupling from 1.9" to 4-1/2",Casing coupling fro4-1/2"to 13-3/8" 2.Grade:J55, K55, N80-1, N80-Q, L80, C90, P110 3.Type: NU, EU(tubing coupling), STC,LC,BTC(casing coupling). 4.We also supply permium thread products by