It has electro-chemical sensor that gives early warning to the user and features dual color LED to indicate battery status as well as sensor health
Product Attributes :
Product Type : Carbon Monoxide Alarm
Audio Alarm : 85dB at 10'
Power Source : (3) AA Alkaline Battery
Operating Temperature : 40 - 100 deg F
Size Description : 4 1/2" W X 1 1/2" D X 2 3/4" H
Trade Name : Kidde 9CO5-LP