The OSI-RE-SS is really a reflector- style linear optical beam smoke detector intended to operate for a component of hearth alarm systems. The beam operates primarily on the basic principle of light obscuration utilising an Infra-Purple beam. OSI-R-SS is a 4-wire conventional reflector-form linear optical beam smoke detector to be https://www.firesense.co.uk/type/conventional-fire-system/conventional-beam-detectors/