The FCP-500 Conventional Flush-mount Detectors are UL Listed, open area photoelectric smoke detectors. Use them with commercial fire protective signaling systems and household fire warning systems (see NFPA 72, the National Fire Alarm Code).These smoke detectors are available as a photoelectric smoke detector or as a multi-sensor detector with an additional carbon monoxide (CO) sensor. The detectors are ideal for areas where increased levels of dust and fibers are expected. Each type is offered in white or transparent with color inserts.These smoke detectors satisfy the most demanding aesthetic requirements. Their ultra-low profile design offers flush ceiling mounting. The detectors and covers in the P versions are supplied with reversible printed color rings in 32 colors for individual color matching.