Technical Parameter :
* Copper fin of selective black chrome surface.
* Absorptivity: 94%-95% Emission: 10%-15%
* Fin standard dimension:
  1840 x 125 x 0.15 mm (length x width x thickness)
* Copper tube standard dimension :
   Riser tube : 1880x10mm, (length x OD) thickness : 0.45mm or 0.6mm
   Head tube: 1000x25mm or 22mm (length x OD), thickness: 0.6mm or 0.8mm