First Alert CO600 Plug-In Carbon Monoxide Detector Keep your family safe with this easy-to-use plug-in carbon monoxide alarm; it works with any standard outlet Features an advanced electrochemical carbon monoxide sensor that accurately detects carbon monoxide levels, no matter where the detector is placed in the room A loud 85-decibel alarm sounds when Carbon Monoxide levels reach dangerous levels To ensure complete protection make sure to place one on each level of your home and in each bedroom 7-year limited warranty; equipped with end-of-life signal chirp, so you know when its time to replace the unit for safety All First Alert CO alarms are rigorously tested to meet UL standards