meterial:low carbon steel tube popular size: diameter4mm,4.76mm,6mm,6.35mm, ... double wall coil weld steel tube, single wall high frequency weldtube, plated copper steel tube, zn coated tube ,condenser ,evaporator.Products are ... been export to Europe, America, the Middle of East, Africa and South-East of Asia. "Quality is first , credit ... and Certificate of Enviroment Management low carbon steel tube