Combination Smoke Detector and Carbon Monoxide Detector Can Detect the threat of these Two Gases.Carbon Monoxide Detector alarm Using High accurate Electrochemical Sensor, alerts you to Carbon Monoxide Danger.Photoelectric Sensor Detects Smoke, Smoke Detector While Minimizing false alarms.Smoke CO Detector Operated unit installs quickly and easily without an electrician at home or bedroom.LCD display concentration PPM, real-time monitoring to protect your safety