Announces “Fire, Carbon Monoxide, Low Battery, or Smart Hush™" activation.\Features\ - 120 VAC w/ 2AA battery backup (batteries included)\ - Interconnects up to 24 Kidde devices (18 initiating)\ - Electrochemical sensor\ - 85 dB at 10'\ - 5 3/4" x 1 11/16"\ - 1 lb\ - 10-year warranty\ - 1/Each Model Number: KN-COSM-IB|UOM: EA