No electricity or battery, powered by heat. Healthy and economical: Wood stove fan for wood burning fireplaces, works with the heat produced by your fireplace, wood stove or pellet stove. Effectively dispersing warm air throughout your room Auto-start: Start working when the surface temperature under the fan reaches about 50 degrees Celsius, working with a temperature between 50 degrees Celsius and 340 degrees Celsius. The higher the stove temperature, the faster the blades rotate. Slow down and stop when the stove cools down Save your bill, more efficient: Make full use of the heat from your wood stove and disperse it throughout your room. The fan circulates warm air at a rate of 270 CFM (cubic feet per minute), the maximum rate will reach 360 CFM, and uses 28% less wood. You can enjoy the warmth in your room, increasing your comfort 【Safety Design】A bimetal safety device.The fan comes with a bimetal safety device in the fan base. When the surface temperature exceeds about 250