First Alert CO410 Carbon Monoxide Detector

The First Alert CO410 carbon monoxide alarm uses an electrochemical carbon monoxide sensor-the most accurate technology available. Its easy-to-read backlit digital LED display gives you a clear read-out of current CO concentrations in parts per million. It is powered by two AA replaceable batteries giving you peace of mind during power outages. The test/silence button both silences a non-threatening alarm and low battery warning and allows you to test the unit's functionality. The alarm performs its own internal test as well. The unit monitors and re-alarms if carbon monoxide levels persist sounding a loud 85-decibel horn. An audible and visual low battery signal alerts you to replace the battery.