Enclosure: The FACP components are typically housed within a sturdy enclosure to protect them from environmental factors and unauthorized access. The SBBRKSM easichange® kit replaces the discontinued BRK 660MBX optical and 670MBX ionisation smoke alarms and fits onto your current BRK twist-healthy alarm baseplate so there is not any require https://www.firesense.co.uk/type/addressable-fire-system/addressable-fire-alarm-control-panels/