... ,WT:6-70mm,length:6-12m or according to the requirement of clients.4.Excutive standards:GB,ASME API5L.ASTM A 106 ... /A53,Despite of the above standards,we can also supply seamless ... so on,and also develop new products according to the requirements of our clients!5.Surface:black lacquered,varnish coating or galvanized ...