The OSI-RE-SS is a reflector- type linear optical beam smoke detector designed to work to be a part of hearth alarm techniques. The beam operates primarily on the basic principle of sunshine obscuration utilising an Infra-Crimson beam. Close/span> You can't entry this web site as this item is just not https://www.firesense.co.uk/type/conventional-fire-system/conventional-beam-detectors/