The OSI-RE-SS is a reflector- sort linear optical beam smoke detector created to operate for a component of fire alarm techniques. The beam operates primarily on the theory of light obscuration utilising an Infra-Crimson beam. OSI-R-SS is actually a 4-wire conventional reflector-kind linear optical beam smoke detector for use in https://www.firesense.co.uk/type/conventional-fire-system/conventional-beam-detectors/