The kind of the Ventilators 1.Turbine Air Ventilators 2.Turbine Ventilator 3.Roof Turbine Ventilator 4. ... : Light weight, high revolving speed, strong corrosion resistance, high air exhausting efficiency, sturdy and durable, clean and smooth, uniform color ... work for a long time so as to make fresh air circulating. 2. Good surface self-lubricating performance, superior anti-corrosion, ...