China Pipe Coupling manufacturer Landee provides
OCTG Pipe Turbing Couplings, NU, EU, STC, LTC, BTC Thread, API 5CT, 4 1/2–20 inch, J55, K55, N80 etc.
Product: OCTG Pipe Couplings, API Spec 5CT.
Grade: J55, K55, N80, L80, C95, P110.
Size: 4 1/2–20 inches (4 1/2", 5", 5 1/2", 6 5/8", 7", 7 5/8", 8 5/8", 9 5/8", 10 3/4", 11 3/4", 13 3/8", 16", 18 5/8", 20").
Thread: NU, EU, STC, LTC, BTC.
Standard: API Spec 5CT.