Combined with advanced concepts, new design housing and aerodynamic design impeller, can effectively reduce vibration and noise Same dimension inlet and outlet, fan can be directly connected with duct Adopted impeller by integrate new plastic blade with metal baseboard Integrated impeller and exterior rotor motor, through air flow efficient cooling can extend the fan lifetime Three speeds control, through keeping current waveform smooth to reduce the noise and vibration, with automatic reset thermal protective device for electricity management, light weight, stable running, high efficiency, long lifetime