Material:Hot-dip galvanized Galvanized pipes Thickness : 2.0mm-3.25mm for the steel pipes. Technology : Soaked in a bath of molten zinc so the pipes are protected from rusty. --In comparison, some companies use a cheaper process such as “electroplated coatings”, such steel is not real galvanized steel, those pipes are easily to be rusted. Clamps:Metal They are made of galvanized steel with powder-coating to prevent from rusting. You can test the quality of the clamps with a heavy hammer.