The FSP851 is a photoelectric smoke detector made by Notifier a reputable manufacturer of fire alarm systems This smoke detector is designed to quickly and accurately detect smoke particles in the air signaling an alarm to alert occupants of a potential fire The FSP851 is commonly used in commercial and industrial buildings as well as residential homes to provide reliable fire protection It is compatible with Notifier fire alarm control panels and can be easily integrated into a larger fire alarm system Overall the FSP851 is a dependable smoke detector that helps ensure the safety of occupants in the event of a fire.