The early warning of this electronic Smoke Alarm detector can save your life and property. Recommended by fire fighting service• Battery: DC 9V• Alarm Sound: >85db (3 m)• Alarm Current: <10mA• Low Voltage Alarm: 6.5V ~7.2V• Working Temperature: -10⁰C ~50⁰C• Working Humidity ≤95% ( 40 ± 2⁰ C )• Origin: EU.   Warning: Smoke Alarm CANNOT be substitute for a Fire System