The Kidde® KN-COSM-BA combination carbon monoxide and smoke alarm provides two important safety devices in a single unit. This alarm includes a voice warning system that announces fire, carbon monoxide, low battery and smart Hush™ Activation. The voice alarm eliminates any confusion and clearly warns you and your family of a smoke or carbon monoxide danger, or if your battery is in need of replacement. This technologically advanced combination alarm is battery operated protecting you and your family even during a power outage when many incidences occur. The KN-COSM-BA is an easy to install alarm that is suitable for all living areas and has a 10 years life and a 7 years limited warranty. This alarm uses ionization sensing technology. Leading authorities recommend that both ionization and photoelectric smoke alarms be installed to help insure maximum detection of the various types of fires that can occur within the home. Ionization sensing alarms may detect invisible fire particles (associated with fast flaming fires sooner than photoelectric alarms. Photoelectric sensing alarms may detect visible fire particles (associated with slow smoldering fires sooner than ionization alarms.