Kidde FBA_21010164 Smoke Alarm, 0 Ideal for the living area with 10-year sealed lithium battery and Hush feature to silence nuisance alarms Hassle-free protection - Goodbye late night low battery chirps! Never replace a battery during the alarms operating life and no need to worry about the batteries being removed Always on - Sealed-in lithium battery powers alarm for 10 years - the life of the alarm The right alarm, the right location. - Each of the four smoke alarms includes features designed to address location-specific safety needs, such as an LED light in the hallway End of Life Warning  Alarm chirps every 30 seconds to indicate the unit is in need of replacement