Fire-Lite SD365CO-IV Combination Fire/Carbon Monoxide Detector, IvorySD365CO combination fire and carbon monoxide (CO) detectors are addressable detectors that send separate signals for fire and CO. These multi criteria detectors use four sensing technologies (photoelectric, infrared, heat, and CO) to accurately detect fire and CO alarm conditions and have a high immunity to false alarms. When paired with the B200S WH sounder base or B200S LF WH low frequency sounder base, the SD365CO detectors can generate unique