The Nest Protect smoke & carbon monoxide (CO) alarm does much more than just sound a shrill alarm when there’s danger in your home. It speaks to you, telling you where the danger is and what the problem is. And before it sounds a piercing alarm, Nest Protect gives you a friendly Heads-Up warning that you can silence with a wave of your hand – no more swinging towels or brooms to try to quiet a false alarm. It integrates with your mobile devices and even messages you if the batteries run low, avoiding that all-too-familiar midnight low-battery chirp. Nightly Promise allows you to sleep safe and sound. Before you doze off, Nest Protect shows you its sensors and batteries are working with a quick green glow after you turn off the lights so low-battery chirps don’t rattle your dreams. With Pathlight, Nest Protect’s LED lights act as a night light. When it’s dark, Nest Protect will light your way as you walk underneath it.