AEGISLINK S-RF500 Wireless Interlinked Smoke Alarm

https://youtu.be/QgcPsnQmaWk

Interlinked Smoke Detector, AEGISLINK Smoke Alarm with Replaceable Battery, Wireless Interconnected Smoke Alarm, S-RF500, 1-Pack (Amazon Affiliate)
US: https://amzn.to/3phRKgO