Smoke Detectors & Fire Alarms by FIRST ALERT. Critical for apartments, dorm rooms, hotels, or wherever else you need protection, its ionization smoke sensor is quick to detect fast-moving fires and flammable particles that spread easily—and dangerously. Once a threat is detected, the 85-decibel siren sounds, even in the event of an electricity failure or power outage. Other features include a hinged cover design for fast installation and a locking pin that prevents battery tampering.