The air inlet which is made of high quality engineering plastic 
  injection process has bigger density and more strength. 

 Adding the ultraviolet resist resin into the raw material to extend 
  service life. 

 Easy to be opened, net which is assembled outer would protect 
  damage from birds 

 There is a PS insulation board which is thick as 20mm fill in the 
  inlet to avoid lost of heating in winter. 

 Specification: Width:600mm Height: 320mm, Thickness: 160mm