Suspension structure: stainless steel structure, painted with epoxy-(coal)tar or chlorinated polyethylene after plated with zinc. Enclosure structure: polyester glass steel, with light weight, high strength corrosion resistant, anti aging, long service life. Air duct:kinetic energy recovery type. reasonable air distribution with high efficiency. Fan: Aeroflot epoxy-(coal)tar blade, feature big air flow, high efficiency. low noise and corrosion resistance.