... from the wall thickness of the aluminium muff tube. Extruded fin gives very good corrosion protection to ... the base tube, as the base tube is not visible to the atmosphere ... inbetween the fins. Product Detail: Tube DetailMaterialCarbon Steel(20#,3087,Q235),Alloy Steel,Stainless Steel ... 8mm, generally 2.5-5.0mmThk0.35-0.5mm heat exchanger finned tube