1.the Theory of Its Running Our Nopower Ventilations need not the electric power instead of easily drive the turbine vanes ratating by nature breeze or the temperature difference between indoor and outdoor so as to make true the running without cost..They are the real practical and energy saving products without noise and pollution., so they can save much electric power and labour for users in order to lower the production cost clearly, to improve the working surrounding of the workshop, to rise the working efficiency even to strengthen the quality of the their products. 2.the Constitutes of the Material Our Nopower Ventilations are made of the whole stainless steel which need not maintenance any longer and are of anti-acid ? base and of anti-erosion by the only once investment. The Tongguan?Nopower Ventilations are set up the advanced bearings imported from America which can be assured for about 15 years. 3. Our Model 880 Nopower Ventilators are possessed with the following traits: no power exhausting, saving energy and money; anti- acid - base, anti- erosion, long-lived used; no noise, no pollution, absolutely environmental protection; improving the air quality, raising working efficency;conveniently setting up and so on. They are widely used in chemical industry, light industry, food, medicine, textile and dye, metallurgy, electrical power, construction, tunnel, machine and hotel, cinema and marketplace.