... air ventilation fan 1)Large air flow 2)Low price,low noise 3)High technical,energy saving 4)Copper motor Ventilation fan, turbo air ... ventilating fan series are designed scientifically. Low cost, low noise, good ventilation effect, strong air flow, energy saving, long lasting and ... and dustproof effects.By pumping the air with negative pressure, the fan circulates the air indoor and outdoor, and drive ...