Product DescriptionThe First Alert CO600 Plug In Carbon Monoxide Alarm utilizes an electrochemical carbon monoxide sensor to detect carbon monoxide. The plug in design of this personal carbon monoxide detector means you can simply plug the alarm into a 120 volt wall outlet, and the carbon monoxide detector is ready to go. When CO levels become elevated, a loud 85 decibel alarm alerts you to the threat. Designed to be simple to use, the CO detector has just 1 button that silences or tests the unit, as well as an end of life timer that lets you know when it is time to replace the device.Amazon.comCarbon monoxide (CO) is the leading cause of accidental poisoning deaths in America, yet many people don't know they are suffering from CO poisoning until its too late. Since symptoms of CO poisoning are like the flu, you might not even know you're in danger at first. That's why a carbon monoxide alarm is an excellent way to protect your family. It can detect the CO you can't see, smell or taste in the air. The First Alert CO600 carbon monoxide alarm uses an electrochemical carbon monoxide sensor-the most accurate technology available. Installation is as simple as plugging it in to any wall outlet. The test/silence button both silences a non-threatening alarm and allows you to test the unit's functionality. The unit monitors and re-alarms if carbon monoxide levels persist sounding a loud 85-decibel horn. UL listed.--Bree NorlanderWhat's in the Box One carbon monoxide alarm and user's manual