TG-600B turbine roof ventilator has three parts including the ball part, middle part and base plate. The body diameter is 750mm and the throat diameter is 600mm. There are three kinds of materials they are made of: (A) stainless steel, (B) vanes stainless steel+ others galvanized sheet, (C) vanes aluminum + others galvanized sheet. The volume of air discharge is about 1500-5000m3/h. We guarantee the usage of them for 15 years.