Offer big-diameter& thick-wall spiral pipe standards: SY/T5037 -2000 API,BV,SGS,ISO Certification Material: API 5L A106 GR.B X42-60 seamless stee pipe1 .Size range 1/2"--36"Material: API 5L A106 A53 GR.B X42-X60 20# Q345B2 Grade : A106B A53B 4 pass the API certification5 have a good aftet sales service6 have a perfect quality control