You probably have a smoke detector and carbon monoxide detector at home, but do you have one in your mobile home, van, or bus? Don't let dangerous fumes build up in your living space because, trust us, a fire in your van is the last thing you want to wake up to in the middle of the night. This product is a smart carbon monoxide and smoke detector combo to make sure that you're notified of any dangerous leaks or fires. The electrochemical carbon monoxide sensor is stable and reliable with low current consumption and small sensitivity drift. The LCD displays CO concentration: 000~999ppm, if CO gas concentrations exceeds 100ppm or smoke concentration over 0.1%, the alarm will be activated and the blue LED backlight will flash. Powered by 3x AA batteries (not included) for ultra-long standby time and low current consumption.