The OSI-RE-SS is a reflector- type linear optical beam smoke detector meant to run as being a component of fireplace alarm techniques. The beam operates primarily on the basic principle of light obscuration utilising an Infra-Pink beam. OSI-R-SS is actually a four-wire conventional reflector-variety linear optical beam smoke detector for https://www.firesense.co.uk/type/conventional-fire-system/conventional-beam-detectors/