The Nest Protect is a smart smoke detector. A new generation of devices that distinguishes between steam and real smoke, knows when it is actually necessary to sound an alarm, and informs you about the air quality in your home. In addition to smoke, it also keeps an eye out for hidden carbon monoxide emissions. The Nest Protect runs on batteries but can also be connected to mains power. This is very convenient because it saves you the hassle of replacing batteries. According to Nest, installing it is a matter of minutes and when the device is not connected to the power supply, you can probably do it yourself.