... Extra loud alarm sound AC/DC Powered Interconnectable Photoelectric Smoke Alarm (smoke detector,fire alarm system) Insects Proof1. Non-radioactive ... Low-battery and battery missing warning indicator9. Auto-reset when smoke clears 10. CE, BSI, SAI Global approved, comply ... dB at 3 metersAmbient Humidity10%~90%Interconnect Facility40 smoke detectors and/or heat detectors over 150m maximumSensitivity to ...