The BRK CO5120BNA is hard wired 120V carbon monoxide detector with 9V battery backup in case of power failure. It can be interconnected with up to 12 BRK smoke alarms, and up to 6 BRK smoke/co combination alarms so all units will go in to alarm if any single unit is triggered.
https://www.aartech.ca/co5120bna/brk-carbon-monoxide-detector-120v-with-battery-backup.html



