The FirePro Mini Photoelectric Smoke Alarm has a photoelectric sensor that detects smoke while minimising false alarms. The FirePro Mini Photoelectric Smoke Alarm is powered by a convenient built-in non-replaceable 10 year lithium battery. Measuring in at only 70mm in diameter, this alarm is aesthetically pleasing and guarantees safety and reliability. Complies with: Australian Standards AS3786-2014 Sound Pattern: ISO8201 Decibels: 85dB(A) at 3 metres