Homedepot offers Kidde Hardwired Ring App Enabled Smart Smoke & Carbon Monoxide Detector, AA Battery Backup, Voice Alerts, Interconnected Alarm for $74.98 with free shipping. 

Product Description: 
Safeguard your home with this Kidde Hardwired Ring App Enabled Smart Smoke Carbon Monoxide Detector AA Battery Backup Voice Alerts Interconnected Alarm.