The main indicators of "DC Cooling Fan" in cooling fan for fan performance parameters: air flow: how many cubic meters of air per minute to produce the fan work, the unit is M3min or CFM pressure: the pressure generated when the fan work, in units of mmH2O "DC Cooling Fan" noise: the sound generated when the fan work, mainly wind noise, electromagnetic noise, bearing noise in units of dB-A life: fan does not work, speed is less than 85% of rated speed is considered its life . maturity fan life generally refers to the average life expectancy "DC Cooling Fan" ambient temperature; temperature location, ambient temperature refers to the life of the fan blower work great influence high temperature fan shortened life expectancy, low temperature bearing grease. not work.