The First Alert BRK PRC710V Talking Smoke and Carbon Monoxide Alarm with Built-In 10-Year Battery features a photoelectric smoke sensor and an electrochemical carbon monoxide sensor. The photoelectric sensor detects larger smoke particles from smoldering fires from objects like cigarettes burning on furniture or in trash cans. This exclusive voice alarm not only alerts you whether the threat is smoke or carbon monoxide, but also uses 11 pre-programmed locations to tell you the location of the danger in your home. The battery-operated smoke and CO detector can be installed easily, with no wires or electrician required, and its slim profile will seamlessly blend in with your home decor. A one-touch silence/test button makes it easy to operate. Its built-in 10-year battery will provide continuous power for the life of the detector and continues to protect during power outages.