The OSI-RE-SS is a reflector- style linear optical beam smoke detector created to work being a component of hearth alarm units. The beam operates totally on the principle of light obscuration utilising an Infra-Pink beam. OSI-R-SS is a 4-wire conventional reflector-type linear optical beam smoke detector for use in fireplace https://setbookmarks.com/story18619427/a-simple-key-for-conventional-beam-detectors-unveiled