Carbon monoxide alarm powered by 120 volt plug-in with a battery backup. Digital LED (light emitting diode) display with easy view back light. Displays carbon monoxide concentration in parts per million. Electrochemical carbon monoxide sensor. Loud 85 decibel alarm with mute button, low battery signal, and end of alarm life timer. Alarm plugs into any standard outlet without any additional mounting, plug-in cord offers multiple placement options. Silence/test button. Easy access battery door for (2) AA batteries (included). Meets UL2034 standards.