Casing and Tubing Coupling API 5CT 1.Size:1.9"~20" 2.Material:J55,K55,N80-1,N80-Q,P110 etc. 3.Thread:NU,EU,STC,LTC,BTC,VAM TOP and other special thread type. 4.Standard:API 5L,API 5CT ,ISO 9001:2008 5. Surface treatment: Whole phosphating, or inside phosphating and outside coating NUE:1.9",2-3/8",2-7/8",3-1/2",4",4-1/2" EUE:1.9",2-3/8",2-7/8",3-1/2",4",4-1/2" STC: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". LTC:4-1/2",5",5-1/2",6-5/8",7",7-5/8",8-5/8",9-5/8",20" BTC: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".