This Kidde KN COSM-IB is a 120 volt hardwired combination smoke and carbon monoxide alarm with a voice message warning system that announces fire, carbon monoxide, or low battery. It also includes a smart hush feature that allows temporary desensitizing of the sensor. The unit features the Nighthawk electrochemical carbon monoxide sensor, 9V battery backup for continuous monitoring even during a power outage, a tamper resistant locking feature, and a quick connect plug with eight-inch pigtails. This AC wire-in alarm can interconnect with up to 24 Kidde devices, including smoke alarms, and functions in temperatures from 40 to 100 degrees Fahrenheit and in humidity up to 95%. This dual hazard alarm is the ideal choice when maximum safety is needed for both home and family.