heat operated (needs no power source) quick start function, overheating protection, 50° swivel rotor with 4 blades, movable rotor (can be switched on and off separately), even better distribution of the furnace heat in the room, start temperature at the heat exchanger approx. 50°, optimum running temperature 80°C to max. 350°C, from approx. 90°C the swivel mechanism starts, size LxWxH: 20.5x12x19.3 cm