API 5CT/5L, J55, N80, manufacture of seamless steel pipe for coupling stock.coupling stock: Grade: A25, A42, B42,X42,X46, ... X52 seamless steel pipe for coupling stock Typeseamless steel pipe for coupling stockBrand NameTMSSPStandardAPI 5CT/5LGradeA25, A42, B42 ... :+86-22-88610332,28619678Fax:+86-22-28619678 seamless steel pipe for coupling stock