2nd GENERATION Nest Protect (battery) has been completely redesigned. It has an industrial grade smoke sensor, can be silenced from your phone, tests itself automatically and lasts for up to 10 years. It also tells you what’s wrong and can even alert your phone. Alarm updates wherever you are Nest Protect alerts your phone when something’s wrong when you are not home. In the unfortunate instance when something isn’t quite right, the Nest Protect speaks up to tell you if there is smoke or carbon monoxide, and where the danger is. It is also the first alarm you can silence from your phone. Simply download the Nest app to your Smartphone to gain full control of the situation. Accurate detection Equipped with its Split-Spectrum Sensor, Protect uses two wave lengths of light to detect smoke from fast and slow-burning fires. What’s more, its humidity sensor and advanced algorithm looks for steam to reduce false alarms. Always be in the know The smoke and carbon monoxide alarm tests itself so you don’t have to. Taking over 400 checks a day, it will be sure to let you know if things aren’t quite as they should be. Such a commitment will last for up to 10 years thanks to the long-life sensors. Sleep easy Pathlight will light your way at night and the brightness can even be adjusted in the Nest app so you can rest easy. The Nest Protect also has a green glow when you turn off the light to show you that everything is OK, so no more rude-awakenings by a low battery. Easy installation Nest Protect only takes minutes to install. Connecting to Wi-Fi and setting them up with your iPhone, iPad, or Android device also takes just a few minutes. Every Nest Protect in your home will connect to the others automatically. And because this smoke detector is battery powered, you can position it anywhere in the home. System requirements Wi-Fi connection Mobile or tablet with iOS 8 or later, or Android 4 or later Free Nest account Accessories included: Six long-life batteries Back plate Four screws User guide Welcome guide 2-year limited hardware warranty Please note: The alarm should not be installed in locations where the normal ambient temperature is below 4°C or exceeds 38 °C. Humidity range: 20% RH to 80% RH (non-condensing).