"220V Cooling Fan" single ball is the traditional oil bearing improvements, sliding friction and rolling friction hybrid form, in fact, is to use a ball bearing with a way to reduce oil bearing double ball bearing of costs, "220V Cooling Fan"between "the rotor and stator are lubricated with the ball, and with oil. It overcomes the short oil bearing life, running instability problems, but rising costs are extremely limited. "220V Cooling Fan" single ball bearing absorbs the advantages of oil-bearing and double ball bearings, bearing life will be raised to 40,000 hours, the disadvantage is added after the ball, run the noise has increased, but still less than the double ball bearings.