The OSI-RE-SS is actually a reflector- variety linear optical beam smoke detector intended to run for a part of hearth alarm devices. The beam operates totally on the theory of light obscuration utilising an Infra-Crimson beam. Near/span> You can not accessibility this site as this product will not be obtainable https://www.firesense.co.uk/type/conventional-fire-system/conventional-beam-detectors/