Legrand flush mount smoke detector. This new alarm uses photoelectric technology that aims to provide optimum protection against smoldering fires. It is inter-connectable and it can be connected to a maximum of 20 units. No more battery charging, the lithium battery eliminates the need to ever change the battery.
Replacing the entire unit after 10 years of use.
The flush mount uses the same cut out as a 90mm downlight. This means any
downlight with these measurements can be easily replaced to house this unit. Ideal
solution for residential and commercial properties.
Read more here: http://www.legrand.com.au/products/smoke-alarms/flush-photoelectric/