The OSI-RE-SS is often a reflector- sort linear optical beam smoke detector designed to function as a element of fireplace alarm techniques. The beam operates totally on the principle of sunshine obscuration utilising an Infra-Pink beam. OSI-R-SS is really a four-wire conventional reflector-type linear optical beam smoke detector for use https://www.firesense.co.uk/type/conventional-fire-system/conventional-beam-detectors/