Know more, worry less. The new Nest Protect looks for fast burning fires, slow, smoldering fires and invisible carbon monoxide. It speaks up to tell you what the problem is and where it is. It can also give you a friendly Heads-Up before it has to sound the alarm and you can hush it with your phone. In case you’re not home, Nest Protect alerts your phone when the alarm goes off or the batteries run low. It also gives you peace of mind by testing itself over 400 times a day and showing you everything’s working with a quick green glow when you turn off the lights.