The OSI-RE-SS is a reflector- form linear optical beam smoke detector created to work being a component of hearth alarm systems. The beam operates totally on the principle of sunshine obscuration utilising an Infra-Red beam. OSI-R-SS can be a 4-wire conventional reflector-style linear optical beam smoke detector for use in https://www.firesense.co.uk/type/conventional-fire-system/conventional-beam-detectors/