1.The ball diameter (body diameter) is 880mm, and the throat diameter (inner diameter) is 680mm. 2.The volume of air discharge is about 2600 to 6500 CBM/H. 3.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. 4. We can design and manufacture other sizes according to your demands. 5. The Values of the Nopwer Ventilations A. They can exhausted the hot air, waste gas, dust and other harmful gas meanwhile the fresh air outdoor can come into the workshop. Improving working environment,making the workers more energetic and to increase the benefits of the company.B. Lower the users production costs. Our Nopower Ventilations belongs to the products which need not electric power and other costs.