For the US the Listener works quite well. I have 8 Google Nest Protect sensors and like them very much. I am extremely disappointed with Google in thier direction for interoperability at this point. I have two listeners, one on each floor within a few inches of a Nest Protect. Be aware that when you have a listener and want to test your smoke alarms (any smoke alarm) you need to disable the listner or put your Ring Alarm is self-monitor mode. The smoke alarm signal to the monitoring company is an immediate dispatch, not a call first situation. There is a Ring fact sheet in the FAQ’s describing this.