... axial ventilation fan,ventilator,rectangular duct fan,noiseless exhaust fan,heavy duty exhaust fan,tunnel ventilation fan, vane axial fan,centrifugal blowers ... strong air flow, energy saving, long lasting and high efficiency. The stainless steel kinds are waterproof and ... with credibility!Contact: Ms AnnieCel:0086 15866595521 high velocity drum fan from professional manufacturer 900mm-1400mm