The air duct is equipped with a filter blocking net to effectively filter soil impurities and protect the internal cleaning of the fan The built-in muffler sponge in the air duct cushions the vibration and muffles the sound, and only hears the sound of the wind Die casting cold rolled aluminum cast rotor, steel shaft stator made of cold rolled silicon steel sheet Artificial special C&U bearing fully sealed steel bearing resistant to 180℃ high temperature, high speed dust, low noise long service life Surface phosphating shot blasting electrostatic spraying, color does not drop paint, scratch resistance