The RV2 Radon Ventilator exhausts radon and other harmful soil gases and allows fresh outdoor air to replace them. At 220 CFM, the RV2 ventilates a 20’ x 40’ x 3’ crawl space over 5 times per hour while using only 40 watts. Simply mount the unit against a vent opening with the included hardware and plug it in. For even greater results multiple units can be installed. Run it continuously or with a plug-in timer. Also helps reduce crawl space humidity.