Products with No power fan is to promote use of the nature of the natural wind speed turbine rotation of the fan and the indoor and outdoor air convection principle, any direction parallel to the air flow, accelerating and converted to a bottom-up flow of air perpendicular to improve the indoor ventilation exchange An apparatus for gas effect. The fan is no electricity, no impatient tone, long-term operation. According to the the air natural laws and the principle of airflow, rationalization set in the top of the roof, the rapid discharge of hot air and polluted indoor gas to improve the indoor environment. The product attributes turbine fan is the use of natural wind and indoor and outdoor temperature difference between the air caused by thermal convection to drive a turbine to rotate to the use of centrifugal force and negative pressure effects of the the indoor stale hot air discharge. Use unpowered fan purposes: to generate air convection row of cooling gas. 2, to reduce the air conditioning load, increase indoor fresh air. 3, extracted roof moisture, Meiqi, steam, and keep the roof dry. 4, instead of heavy-duty electric blower, reduce stent cost savings in electricity, minus the noise. Installation and maintenance zero cost operation costs, the objective of energy efficiency, the economic installation costs, low maintenance costs. Note unpowered fan special energy efficiency curved fan blade is the best results of scientific computing, to strictly ensure the working condition never taboo to let rainwater intrusion. Exhaust efficiency is high, as long as not less than 0.2 meters in the breeze or the indoor and outdoor temperature difference of more than 0.5 ° C, to light, to function effectively. 2, the central axis of a fine steps, so never deformed under high-speed operation of the fan blade of the turbine, which greatly improve the service life of the fan. 3, variable angle design of the neck can make the fan 0-22.5 degrees a slant under arbitrary installation, the installation works is very simple, ordinary people can be installed to complete within about thirty minutes. Other fan no electricity, no impatient tone, long-term operation. According to the the air natural laws and the principle of airflow, rationalization set in the top of the roof, the rapid discharge of hot air and polluted indoor gas to improve the indoor environment. Description of a transaction, deal face to face 2, online trading 3 auction Buy transaction