The Kidde KN-COSM-XTR-BA uses breakthrough technology to offer a fast response to real fires, including smoldering and fast-flaming, as well as protect you from carbon monoxide and dramatically reduce the chance of nuisance alarms. In addition, the Intelligent Alarm contains a voice warning that clearly states the present danger – smoke or carbon monoxide – and announces “FIRE!” or “WARNING! CARBON MONOXIDE!” The Intelligent Alarm combines the detection capabilities of an ionization smoke sensor – which is more likely to detect smaller, less visible fire particles, like those produced by flaming fires – with that of an electrochemical sensor, which is used to detect CO.