First Alert SMI100-AC, 9120B Replacement Hardwire Interconnect Smoke Alarm with Battery Backup, 1-Pack

First Alert's Precision Detection advanced sensing technology complies with new industry standards to reduce cooking nuisance alarms and provides early warning in the event of a home fire emergency., Through early warning interconnect, when one alarm sounds, all compatible alarms will sound, Battery backup provides continuous protection during power outages, Alarm indicator visually identifies the unit that initiated the alarm, Quick Connect Plug included allows for easy installation with no need to rewire