21010407 Robertshaw Smoke Alarms

The Kidde Smoke Alarm models are sealed-in lithium battery devices available with either photoelectric or ionization sensing technology. Photoelectric sensing alarms are designed to detect visible particles (associated with smoldering fires) sooner than ionization alarms. Ionization sensing alarms are designed to detect invisible fire particles (associated with flaming fires) sooner than photoelectric alarms. This series includes models for living areas, bedrooms, and hallways. All models offer worry-free features to make installation easy and to help users aware of replacement requirements.