Tjernlund V2D UnderAire Crawlspace Ventilator Fan Moisture Mold Reducing Power ventilate musty, damp crawl spaces through existing passive vents Faceplate is sized for ventilation openings through standard block foundations 220 CFM, 40 watt maintenance free exhaust fans Includes adjustable dehumidistat, freeze protection limit and 6 foot grounded power cord Faceplate can be trimmed to match non-standard foundation openings.Dehumidistat control also will not operate if the freeze protection thermostat senses low outdoor temperatures