When consumers buy "220V Cooling Fan", to look at the instructions to see if the mandatory certification quality system certification, whether there is inspection standards certification; and now promote "green carbon", depends on whether the national level energy efficiency standards. "220V Cooling Fan" major component making noise is the motor, in the selection of "220V Cooling Fan" must listen whether the noise when the motor is running, to see it in operation whether jitter is stable; good motor let you in quiet environment, only to hear the wind, "whispers", ultra-quiet fan blowing air is good.