"220V Cooling Fan" inner and outer double blade angle different design, so that can simulate the effect of natural wind. Using a brushless DC motor can be done very energy-saving, only the minimum power 3W. Also "220V Cooling Fan" is muted, a sound file to run only 13dB, it is the sound of a butterfly flapping its wings level, of course, this is only the official data, a real friend used to say, really quiet. In addition there are two small ways, but also reflect the design intentions, this "220V Cooling Fan" is assembled without any screws, the components snap together cleverly, to complete the assembly. Version of the Japanese market in the terrestrial fixed chassis built-in battery, so you can move in indoor use, if the surrounding inconvenient to use sockets.