Safety shouldn't be annoying. The Nest Protect smoke and carbon monoxide (CO) alarm quiets down when you wave - no more swinging towels or brooms - and sends a message to your phone if the alarm goes off or the batteries run low. Instead of just chirping and howling at you, Nest Protect speaks with a human voice. It gives you a friendly Heads-Up before burning toast turns into an emergency, and tells you which room the smoke or CO is. Low-battery chirps ever rattle your dreams? Nightly Promise shows you its sensors & batteries are working before you doze off.