Google Nest Connect
Google Nest Connect works with the Nest Secure Alarm system. It keeps Nest Guard and Nest Detect connected when they’re placed far apart, (an extender) especially in larger homes. And with battery backup, Nest Secure stays up and running when power goes out.
Google Nest Connect is powered by 3 Energizer Ultimate Lithium (L91) AA batteries that are widely available. Be Smart Computing recommends changing these once per year (Labor Day) with all of your other battery backup strategies.