The First Alert® CO400 Battery-Operated Carbon Monoxide Alarm utilizes an electrochemical carbon monoxide sensor to detect carbon monoxide. This carbon monoxide detector is battery operated, making it portable and easy to use, even in the event of a power outage. When carbon monoxide levels become elevated, a loud 85-decibel alarm alerts you to the threat.

• Detector features a single test/silence button for efficient testing
• Battery-operated detector is portable
• Loud 85-decibel alarm sounds when CO levels are detected
• CO detector alerts you to carbon monoxide