CO850MBXi-Carbon-Monoxide-Alarm-Mains-Powered-with-Battery-Backup-BRK-CO850MBXI-p-The-BRK-reg-CO850MBXi-Carbon-Monoxide-Alarm-uses-the-latest-electrochemical-sensing-technology-to-continuously-monitor-for-the-presence-of-deadly-carbon-monoxide-CO-in-the-home-It-has-power-alarm-&-fault-indicators-&-an-instant-test-reset-feature-p-p-The-alarm-is-230V-mains-powered-with-a-9V-alkaline-battery-backup-that-provides-power-to-the-unit-in-the-event-of-mains-failure-Up-to-12-compatib