Industrial Properties Combine with weather Manage, fireplace, everyday living safety and entry Command techniques on one monitor. OSI-R-SS is usually a four-wire conventional reflector-type linear optical beam smoke detector for use in fire alarm methods. The beam operates primarily on the principle of light obscuration utilizing an infrared beam. Acct: https://www.firesense.co.uk/type/conventional-fire-system/conventional-beam-detectors/