First Alert, 1046858, Alarm, Battery Power Source, Ionization Sensor, Alarm: Smoke, 85 dB Sensitivity, White, 2.25 in H x 5.7 in W x 5.7 in L Dimensions
Sensor Information: Smoke particles of varying number and size are produced in all fires. For maximum protection, use both ionization and photoelectric sensing technologies. Ionization alarms are generally more sensitive to fast flaming fires and photoelectric alarms are generally more sensitive to smoldering fires.