High-speed "Micro Cooling Fan" Always use low speed fan uses ball bearing low-cost oil bearing. Oil-bearing fan with only one bearing; and require two ball-bearing fan bearings, single ball bearing, oil bearing fan used copper-based sintered powder made by using lubricating oil bearing need to reduce the number of sliding friction, lubricants Stuttgart made from lithium grease oil blend. "Micro Cooling Fan" With the long run, the oil inside the bearing will evaporate and dry, the friction coefficient increases, fan operation affected may appear different sound, speed Pianman not even turn on. The ball bearing is replaced by rolling friction sliding friction, low coefficient of friction and to overcome the shortcomings of the friction coefficient is apt, therefore "Micro Cooling Fan" strong operating stability, life is relatively much longer.