As already mentioned, some "220V Cooling Fan" at the outlet side of the frame to increase the similarity with the fan shape, but bent and opposite deflector for airflow Adds a "restraint." Can make more concentrated airflow, reduce blind spots, and further enhance the pressure; however airflow disturbance punch with more friction will undoubtedly increase the "220V Cooling Fan" operating noise. Typical for Delta- Delta FFB series axial fan. The famous FFB8012EHE "violence" fan, for example: 8038 standard, ball bearing, 5700rpm, rated voltage of 12V, rated current of 1.35A, the maximum amount of wind 2.270cmm, 20.63mm maximum static pressure of water. It is in fact Axial "220V Cooling Fan" on the basis of specifications 8020 increased 9 height of about 18mm inverted curved deflector.