First Alert GC01CN Combo Explosive Gas and Carbon Monoxide Alarm with Digital Display, 1039760PT

Loud 85-dB alarm can be heard easily. Low-battery warning and end-of-life warning. Easy-to-read backlit digital display allows you to view current and peak levels Plugs into any AC outlet for easy setup; line cord for versatile placement options 9-volt backup battery powers detector in case of power outage; can be replaced without dismounting alarm. 1-touch silence/test button makes it easy to test detector or mute it during false alarm.