The OSI-RE-SS is a reflector- style linear optical beam smoke detector created to run being a element of fire alarm units. The beam operates totally on the principle of sunshine obscuration utilising an Infra-Crimson beam. OSI-R-SS is a four-wire conventional reflector-type linear optical beam smoke detector to be used in https://www.firesense.co.uk/type/conventional-fire-system/conventional-beam-detectors/