First Alert Onelink Smart Smoke and Carbon Monoxide Alarm provides dual protection for your home with 2-in-1 detection capabilities. This battery-powered unit features wireless interconnectivity, allowing all compatible alarms to sound together when one is triggered. Stay informed with emergency notifications sent directly to your smartphone and clear voice alerts that specify the type and location of the danger. It is compatible with Apple HomeKit for seamless smart home integration and includes a 3-cell battery pack designed to last approximately five years. The photoelectric sensor reduces nuisance alarms from cooking smoke while remaining highly sensitive to smoldering fires.