... ventilation fan diameter 310mm 1, Energy saving,high efficiency 2, VAC 1-100-130, airflow: 1900m3/h 3, Low noise ventilation fanec centrifugal ventilation fan ... Backward Curved Type: SC310E3-ACT-00EC exhaust fan1,Energy saving,high ... , welcome you all to visit our booth. ec ventilation fan backward curved diameter 310MM