... appearance and wind resistance AC axial flow roof exhaust fan/ventilator fan Performance introduction WT35(DWT-I),WT4-72( ... houses, office, experimental room, warehouse, etc. The fan can adapt to different version and needs. It can ... hard particles contained should not exceed100mg/m3. The fan consists of impeller,hair dryer,cap ,motor and ... -II)Certificate AC axial flow roof exhaust fan/ventilator fan