The OSI-RE-SS is actually a reflector- kind linear optical beam smoke detector designed to run as a part of fire alarm devices. The beam operates primarily on the basic principle of light obscuration utilising an Infra-Purple beam. OSI-R-SS is often a 4-wire conventional reflector-type linear optical beam smoke detector to https://www.firesense.co.uk/type/conventional-fire-system/conventional-beam-detectors/