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 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 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, Manufacturer: YanFengPro