Equipped with electrochemical sensor and microcomputer-based CO detection circuit, COSTAR® 24VC-e monitors unsafe levels of carbon monoxide in parking garages to protect building's occupants. Ventilation control saves energy by activating fan only when required to maintain air quality. Featuring calibration-free design, unit self-tests electronic circuit and signals fault warning if malfunction is detected. Product meets UL standard 2075 and adheres to strict NIOSH requirements.