Google Nest Protect - Smoke Alarm and Carbon Monoxide Detector - Battery Operated

Nest Protect Smoke and Carbon Monoxide Alarm - 2nd Generation (Battery): Nest Protect reliably detects and alerts you to the presence of smoke or carbon monoxide in your home. The alarm speaks to you in a calm, clear, human voice, telling you the location of the danger. It also provides smartphone alerts and battery status updates to help protect your home.