The OSI-RE-SS is really a reflector- type linear optical beam smoke detector meant to run for a element of fire alarm devices. The beam operates primarily on the basic principle of light obscuration utilising an Infra-Pink beam. OSI-R-SS can be a 4-wire conventional reflector-form linear optical beam smoke detector for https://www.firesense.co.uk/type/conventional-fire-system/conventional-beam-detectors/