Nest Protect is the smoke alarm that thinks, speaks, and alerts your phone. This smoke detector and carbon monoxide detector hava a Split-Spectrum Sensor to detect fast-burning and smoldering fires, tests its own batteries, and lasts up to 10 years. It sends phone alerts when something’s wrong.  You can hush the alarm from your phone with App Silence. And it tells you when the batteries are running low, so there are no chirps at 2 AM.  Mobile alerts require working internet and Wi-Fi.