The centrifugal exhaust fan has many advantages: 1) Adopt the system which open and close automatically when the fan works. 2) Centrifugal shutter system and other fitting of shutter made of Nylon, high quality engineering plastics, 100% raw material, high strength, and long service life. 3) The inner steel fitting install in the flange, increasing the security, avoid the stretching change when Nylon system operates. 4) Adopt the injection molded Stainless steel blade, no broken, no distortion, aesthetic and durable. 5) Balance running machinery checked the entire fan blade’s balance; ensure operating steady, low noise, long service life. 6) Adopt the handle as new inset design from our engineer, easy for carry, transport and installation. Also has no affect on the appearance. 7) It made of high quantity aluminum-magnesium alloy, light weight, high strength. 8) We could supply V-belt as the type A or type B, upon the varieties demand of different customers. 9) The high efficient and energy-saving motor passed the national CCC certification. Also protection class: IP55, insulation class: F grade. Model specifications Diameter blades mm Blades rotational speed rpm Motor rotational speed rpm Air flow m3/h Total pressure Noise decibels Import power Rated voltage High mm Width mm Thick mm DJF(a)-780 710 960 960 23000 75 ≤70 750 380 780 780 420 DJF(a)-830 720 660 1400 22000 60 ≤60 550 380 830 830 400 DJF(a)-900 750 630 1400 28000 65 ≤65 370 380 900 900 400 DJF(a)-1000 900 610 1400 30000 70 ≤70 750 380 1000 1000 400 DJF(a)-1100 1000 600 1400 32500 70 ≤70 750 380 1100 1100 400 DJF(a)-1220 1100 460 1400 38000 73 ≤70 750 380 1220 1200 400 DJF(a)-1380 1250 439 1400 44000 56 ≤70 1100 380 1380 1380 400 DJF(a)-1530 1400 325 1400 55800 60 ≤70 1500 380 1530 1530 400 we also produce other kinds of exhaust fans.Welcome you to our Web:http://www.wfsanhe.com. My e-mail:sanhejixie@yahoo.cn