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. The 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| Emergency safety light provides an illuminated escape path| 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.