View on LOZ Suggested Retail: $26.99. VIVOSUN 4 Inch 195 CFM Inline Duct Ventilation Fan Vent Blower for Grow Tent. Powerful Airflow: This VIVOSUN powerful blower with a fan speed of 2500 RPM can create an airflow of 195 CFM; It works efficiently in ventilating grow tents, transferring heat or cool rooms, circulating fresh air, as well as controlling proper humidity, temperature, and air quality for your grow areaQuiet Operation: Fitted with a flow deflector that concentrates the fan stream and cuts turbulent kinetic energy to reduce sound output to just 30 dB, which does not have any harm to your health and will not disturb your work.. 7 CALENDAR DAY FULL REFUND GUARANTEE ON THIS ITEM IF ANY ISSUE IS FOUND THAT WAS NOT DESCRIBED/PICTURED. 7 CALENDAR DAY STORAGE IS ALSO AVAILABLE. SEE NOTES TO BIDDER, IN AUCTION DETAILS, AT THE TOP OF PAGE 1 FOR MORE INFO.