Long : There is a Bi-metal device in the base of the fan.If the surface temperature rises around 300°C , the device gently elevates the front of the fan to protect the Teg and motor : Newly Designed , Larger Air Volume , Lower noise.You don ' for t even know the stove fan is there , but you feel the warmth ! You will enjoy the warm air of a quiet and comfortable environment Safty Design : The stove fan is made with Anodized Aluminum , able to resist high temperature , no deformation and no discoloration even after long for time working under high temperature and Self-Powered : Thermoelectric module acts as a small generator to power the fan ' s motor No batteries or electricity required ! warm air circulation results in greater comfort and reduce wood consumption from your stove Start Automatically : Upgrade technology , faster speed , larger air volume.The heat powered stove fan is designed to circulate the warm air created by a wood / coal or pellet burning.Efficiently circulates warm air throughout the house, Manufacturer: Watreketal