All products according with API 5CT.can make big diameter coupling Have all grade of API standard for thread also.Grade,J/K55,L/N80,P110Thread, BTC,LTC,STC.Size of Tubing , 2 3/8 " - 4 1/2"Outside diamete, 60.32 – 114.3mmWall thickness,4.83-6.88 mmEUE,NUESize of Casing ,4 1/2 "- 20."Outside diameter ,114.3 - 508mmWall thickness, 5.21 – 16.13mmGrade ,J55 / K55/ N80 / L80 / P110Length R1 R2 R3