Alarm smoke talking wireless and co lithium battery. 10-year battery operated wireless talking smoke and carbon monoxide alarm. Wireless interconnect, proprietary radio signal joins multiple alarms together, so when one alarm sounds they all sound. 10-year sealed-in lithium battery, no battery replacement required over the 10 year life of the alarm. Voice Notifications, unit verbally announces "Fire!", "Carbon Monoxide" and other alerts such as "Replace Alarm," which helps the user better understand current status of the unit. Alarm locate feature, quickly find initiating alarm by silencing other alarms in the network. Photoelectric sensor, smoke alarm contains advanced photoelectric sensor that may detect visible particles (associated with smoldering fires) sooner than ionization alarms. Hush will temporarily silence nuisance alarms and will not allow hush mode to be activated unless the unit is in alarm mode.