Good "Micro Cooling Fan", in addition to its high air volume and pressure outside their reliability is suitable important, meantime, fans use the bearing plays a very important effect. Typically use high speed ball bearing fan (ball bearing), while the low speed fan is relatively cheap use of capital self-lubricating bearing (sleeve bearing). Each fan will demand two bearings, a number of standard "Micro Cooling Fan" on the word "BS", is the single ball bearing, BS means "1 ball + 1 sleeve", still with a self-lubricating bearing components of ??? BS is more advanced than the double ball bearings, namely Two Balls. Power "Micro Cooling Fan" is our usual livelihoods of the most common household appliances, is a use of a motor-driven fan rotation, then let the air to accelerate the flow of household appliances, it is generally used to allow air circulation may cool hot weather.