* Copper fin of blue sputtering coating.
* Absorptivity: 92-93% Emission: 7%-10%;
* Fin standard dimension :
   1840 x 130 x 0.15 mm (length x width x thickness);
* Copper tube standard dimension:
   Riser tube: 1880mm x 10mm,
      (length x OD) thickness 0.45mm or 0.6mm;
   Header tube: 1060mmx22mm(or 25mm)x0.6mm (or 0.8mm)