Electrical motor: Shaded pole motor structure. Impedance protect Frame: Casting Al-alloy with black paint, anti-corrosion, anti-oxidization Fan leaf: Once moulded by pour mold, PBT+30% grass firbe+VO anti-burning preparation Withstand voltage: Creep age current: 0.5mA, withstand voltage 1800V/MIN Insulating grade: B Protecting grade: IP54 The settting bolt of fan: M4X8 Weight of Unit fan: 225g