It features the use of blinking lights that indicate when your sensor is operating and when it has an issue. The producers of this model have eliminated the hassle associated with dealing with smoke alarms through their design of a smoke detector with an automatic battery self check system. The Nest Protect alerts you with help from its voice feature. This differs significantly from the regular smoke detectors that make use of the beeping tones to indicate danger. Whenever there’s potential danger such as the release of carbon monoxide in your living area or the smell of burnt toast, your Nest Protect has been engineered to talk to you about it and keep you alert. Every message relayed is spoken and can be received either on your cellular devices or through phone notifications.