You can't see or smell it, but carbon monoxide gas is poisonous. It can come from automobiles and other sources such as chimneys, wood or gas stoves, gas dryers, water heaters or gas or oil furnaces. Your kitchen, garage, basement or fireplace area are likely locations where the gas can build to dangerous levels. That's why the Consumer Product Safety Commission advises that every home have a detector mounted near bedrooms and utility areas. Our Detector plugs into any standard 120 volt wall outlet and continuously monitors for carbon monoxide. It sounds a warning if low levels of carbon monoxide are present, and triggers a loud 85 decibel alarm at hazardous levels. Includes self-test feature, test/reset button and 5-year comprehensive warranty. UL approved. This deluxe model features a battery backup to provide continuous protection even during power outages and backlit digital display that illuminates carbon monoxide levels and battery life.