Round frame "220V AC Cooling Fan" To meet some special installation requirements - such as circular duct, circular heat sinks, easy to use, "just like" the fan, but need to outline the role of diversion circular frame fan should be born.
Frameless "220V AC Cooling Fan"
In some cases, the frame of the diversion effect is not necessary, or even a negative impact or impede the installation exist, it will be "abandoned". At present, more common in some circular radial heat sink, especially built-in fan. Typical for Zalman CNPS7000A, and Intel Prescott boxed mix of "Sunflower."
External magnetic "220V AC Cooling Fan"
Spindle Bracket will spoiler, motor and bearings will also form a "blind spot", at least in close unfavorable airflow cover the entire heat sink, if not eliminate, it should minimize the blind spot area. But with current technology, bearings for rotating blades remain indispensable, YEN SUN will be in the motor has been improved.