This First Alert SCO5B is a combination smoke and carbon monoxide alarm for the residential and institutional setting. The combination of a photoelectric sensor for smoldering fires and an electrochemical carbon monoxide sensor makes this an unbeatable unit in settings like hotels, motels, dormitories, multifamily dwellings, and the sleeping rooms of hospitals. The ionization carbon monoxide alarm meets new construction requirements and is listed to UL 217 and UL 2034 standards. The alarm is battery powered and requires two AA batteries. A 7-year warranty ensures this alarm is the ideal choice in any home or dormitory setting where an early warning can make a lifesaving difference.