duct ventilation fan usually used in bathroom,meeting room start fast, smooth rotation, large displacement, and low noise, provincial power, and easy to install, etc. We have different duct ventilation models: ModelRated Voltagem3/hOutlet sizeQTY(Pcs)MEAN(cm)APJ-12220V/40W132m3/min Φ100873*27*53APJ-16220V/40W288m3/min Φ100874*33*64APJ-18220V/40W410m3/min Φ100874*36*70