Exhaust fan has features: 1)low total pressure, 2)huge air volume, 3)low noise, good energy ... (mm)Blade speed (r/min)Air volume (m3/min)Total pressure (Pa)Noise (DB)Input power (KW)Rated voltage (V) ... , low consumption of electricity, good cooling effect and so on. It can be used in the workshops of the factory ... of the product can reach the international standard. Negative-pressure 9FJ-A/B exhaust fans