1)long working life time 2)imported bearing,high-strength 3)steady long circulation 4)low noise,big wind volume Series of Cone exhaust fan features:1) Reasonable cone designing, low noise, big air flow, strong ventilation, low operating cost.2) Imported bearing, high-strength, low noise, durable.3) Using air downstream principle, pvc shutter or aluminum shutter, antioxidant, light weight, no ...