A whole variety of annunciators, detectors, manual phone factors and modules which can be compatible While using the Morley SMX and STX fire alarm panels The SBBRKSM easichange® package replaces the discontinued BRK 660MBX optical and 670MBX ionisation smoke alarms and suits onto your present BRK twist-match alarm baseplate so https://www.firesense.co.uk/type/addressable-fire-system/addressable-fire-alarm-control-panels/