The Kidde 440375 is a battery operated, single station smoke alarm. This unit provides a level of protection that you have come to expect in a Kidde product. The Kidde 440375 is designed to alert you and your family to the dangers of smoke and fire. This smoke alarm features an ionization sensor that protects best against fast flaming and other types of fires. Powered by a 9V battery and offers a Hush® feature that temporarily silences nuisance alarms.