First Alert CO400 Carbon Monoxide Detector

The First Alert CO400 carbon monoxide alarm uses an electrochemical carbon monoxide sensor-the most accurate technology available. The permanent sensor lasts up to five years. It is powered by two AA replaceable alkaline batteries giving you peace of mind even during power outages. The test/silence button both silences the alarm and allows you to test its functionality. 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. 5 year limited warranty. UL listed.