YUEMI 3-Blade Stove Fan Ultra Quiet Fireplace Wood Burning Eco friendly Fan Wood/Log Burner Fan,Stove Fan Heat Powered Fireplace Fan for Wood/Log Burner/Fireplace Save 20% Fuel Cost Start automatically:Start work when the surface temperature under the fan reaches around 50(122),working with a temperature between 50(122) centigrade degree to 350(662) centigrade degree. The higher temperature of the stove, the faster the blades spin.Slow down and stop as the stove cools. No electricity or battery,powered by heat.Healthy and economical!:Wood Stove Fan for Log Burning Fireplaces,gets power from the HEAT produced by your fireplace, wood-burning stove or pellet stove.Effectively dispersing warm air around your room. Safty design:The stove fan is made of Anodized Aluminum.The fan comes with a bi-metallic safety devicein the base of the fan.When the surface temperature rises above around 250, it will gently lift the front of the fan to protect the TEG and motor. The fan will automatically recover normally as the surface temperature decreases. Save your bill, more efficiency:FULLY utilize the heat from your wood stove and disperse it to your room.The fan circulates warm air at a rate of 150 CFM(cubic feet per minute), You can enjoy warmth in you room,increasing your comfort. Unique blade design:Working quietly,more air flow.Feature with the unique blades design,The stove fan can drive more warm air with silent work.No noise! You will enjoy the warm air in a quiet and comfortable environment.