VIVOSUN 4 Inch 203 CFM Inline Duct Ventilation Fan with Variable Speed Controller POWERFUL AIR FLOW: Heavy hitting blower with a fan speed of 2500 RPM for an air flow of 203 CFM. Moves air through your target location efficiently for optimal ventilation. RUNS SMOOTH AND QUIET: Powerful fan puts out only 49 dB noise level. Fine-tuned for minimum vibration with a sturdy vegan leather cover that further muffles any sound or vibration. DURABLE BUILD: Galvanized steel parts come factory painted to resist atmospheric corrosion from humidity. Tight, precise construction eliminates rattling and reduces wear and tear to give the element a long life. HIGH TECH DESIGN: The aerodynamically designed centrifugal impeller of this unit delivers strong air flow with a disproportionately low sound profile. Fitted with a variable speed controller and dual flanges for hassle free hookup VERSATILE APPLICATIONS: Ideal for cooling lighting fixtures or controlling hot and humid conditions in grow tents/rooms. Heavy hitting blower with a 203 CFM capacity Low, 49 dB noise level Fine-tuned for minimum vibration Sturdy vegan leather cover muffles any sound or vibration Fan speed of 2500 RPM moves air through your target location efficiently for optimal ventilation Add a compatible 4-inch VIVOSUN silencer to your system to handle noise from displaced air and further reduce the total noise level from your ventilation system Can be used as an air intake or exhaust Frequently used for cooling lighting fixtures or controlling hot and humid conditions in growing spaces<br> Suitable for anything from small to industrial scale grow tents/grow rooms/hydroponics systems Combines with 4-inch air filters, ducting, and noise reducers to suit your needs