Model:LAPB20B-25B-30B(Deluxe type) Detailed Product Description Features: 1) Optimized airflow with low noise and high efficient blowing (piping type) 2) Maintenance free motor 3) Metal fan with excellent performance (strong exhaust type) 4)Bi-directional working shutter Ventilator Specifications: 1) Front panel dimensions: a) 305 x 305cm b) 350 x 350cm c) 400 x 400cm 2) Opening dimensions: a) 250 x 250cm b) 300 x 300cm c) 350 x 350cm 3) Air Flux: 500, 800, 1100 cubic meter per hour 4) Material: ABS