Know more, worry less. Nest Protect speaks up to tell you what the problem is and where it is. It will even message your phone when the alarm goes off. And you can check on things at any time with the Nest app. Nest Protect can also see the carbon monoxide you can?t. Or if there?s only a little smoke from just burning the toast, it gives you a friendly Heads-Up. It also gives you peace of mind by testing itself constantly and showing you everything?s working with a quick green glow when you turn off the lights. Sweet dreams.