... air centrifugal exhaust fan 1) CE certificate. 2) Stainless steel blade 3)Big volume, low noise 4) Waterproof, dustproof Product features 1) Fan Frame: ... 2) Blade: 6 pieces stainless steel blades and the fan has all passed the experiment of homeostasis with big air ... is aluminum magnesium alloy injection molded, light weight, high-strength.4) Bearing: France imported bearing, high intensity, low noise, ...