Product Name Api Threading Oil Pipe Casing Tubing Coupling Material J55,K55,N80,L80,P110.etc colour red, green, white Standard API type Coupling, casing coupling, tubing coupling Thread EUE, NUE, STC, LTC, BTC Thechnique seamless Application Connecting two oil tubing or casing pipes Specification range range:2-3/8", 2-7/8", 3-1/2", 4", 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" WT:4.24-16.13mm Testing NDT etc related rules of API 5CT and 5B