The First Alert Model CO410 is a battery operated, 3V (two 1.5V AA batteries) single station carbon monoxide alarm specifically designed for residential and institutional applications including sleeping rooms of hospitals, hotels, motels, dormitories and other multi-family dwellings as defined in standard NFPA 720. This unit features an electrochemical CO sensor, an 85dB horn, a silence feature, and a red LED that blinks to indicate unit is receiving power. The front access battery door allows battery access without removing the unit from the wall. The low power warning indicator will cause the alarm to "chirp" when the batteries need replacing. The low power warning indicator can be silenced for up to 8 hours. Complete with a backlit digital display that shows visual confirmation of CO levels. It also has Peak Level Memory, which remembers and displays the highest levels detected when the Peak Level button is pressed. Backlight illuminates only when any button is pressed or unit is in alarm. Includes mounting anchors and screws.