FireAngel Environmental Measurements Accessories Carbon monoxide detector 625579 - FireAngel FA3820-EUX10, The FireAngel FA3820-EUX10 is a carbon monoxide detector with a 10-year battery life. It is used to detect dangerous levels of carbon monoxide gas in homes and businesses. The device provides an audible alarm for early warning of CO presence. FireAngel FA3820-EUX10 Carbon Monoxide Detector, 10-Yr Battery, LED Alert