First Alert Hardwire Smoke Alarm, Dual Sensor

Price: $44.99
(as of Oct 05, 2026 17:00:57 UTC – Details)


First Alert SM300-AC, Interconnect Hardwire Dual Sensor Smoke Alarm with Battery Backup, 1-Pack
First Alert’s Precision Detection advanced sensing technology reduces cooking nuisance alarms and delivers early warning
Dual smoke sensor technology provides optimal protection for both smoldering and fast flaming fires
Interconnects with most First Alert and BRK alarms so when one sounds, all compatible alarms sound to provide an early warning
Latching Alarm Indicator visually identifies the unit that initiated the alarm or low battery warning. Battery backup provides continuous protection during power outages.
Test/Silence button allows for efficient testing and temporarily silences alarm for up to 8 hours
Customers find the smoke alarm to be a good replacement unit, with one mentioning it’s compatible with the 3120B model. The installation process is easy, and they appreciate the dual sensor design, with one customer noting it includes both photoelectric and ionization detection. The reliability receives mixed feedback, with some customers reporting no false alarms while others experience issues.