Some "220V Cooling Fan" at the outlet side of the frame to increase the fan shape is similar, but curved and opposite baffle for airflow Adds a "constraint." Can make more concentrated airflow, reduce blind spots, and to further enhance the pressure; however, rushing stream disturbance with more friction, will undoubtedly increase the "220V Cooling Fan" operating noise. Moreover, not content with a reverse bend to the outlet guide vanes increase the pressure, using more extreme multi-channel blade design, which is mainly based in two fan blades. Instead dip "220V Cooling Fan" two leaves, bend opposite direction, rotate in opposite directions, are driven by two motors, the maximum amount of wind in the same circumstances, can obtain greater static pressure.