... could be worked in -35C degree. Heat pipe solar collector: Specification:Manifold material and thicknessA, Black or silver aluminum ... alloy , thickness 2.0mmB, Stainless steel 304 2B, thickness 0.8mmHeader pipe ... thicknessDiameter:32mm, thickness 1.0mm copper pipeHeat pipe material and thicknessDiameter:14mm, thickness 0.5mm ...