A mechanical fan is a powered machine used to create flow within a fluid, typically a gas such as air. A fan consists of a rotating arrangement of vanes or blades which act on the air. The rotating assembly of blades and hub is known as an impeller, a rotor, or a runner.3 Speed Level Controller,Motor Over-Heat Auto Protection,Jerk-Free and Wide Area Oscillaton,Powerful Motor for Higher Air Delivery,S AS Blade for Strong wind,Smooth Oscillation,Safety Protection,Unique Oil Reservoir Lubrication for Better Reliablity and Longer Life.