Sealed-In lithium battery: Maintenance and hassle free with prevention from tampering and removal. The alarm is always on, with no battery replacement required for the 10 year life-span of the alarm| Photoelectric sensor to detect visible particles associated with smouldering fires| Single screw-mounting bracket enables quick and easy installation. Alarm is automatically activated once installed| Smart Hush™ button temporarily silences nuisance and false alarms| Test/Reset button tests the alarm circuitry and horn. Resets memory after the alarm has sounded| Talking voice Alarm is more effective at waking than a tone only| End-of-life signal - chirps every 30-45 seconds to signal that alarm needs to be replaced| Deactivation switch disables the alarm to allow for safe battery disposal once the unit has reached the end of its 10-year life| 10 year limited warranty provides peace-of-mind with a decade of smoke and fire detection| Australian Standards approved - complies with Australian Standard AS 3786:2014 incl. Amdt 1 and Activfire listed for quality assurance.