System Sensor DUCTSD Single Sensor 4-Wire Photoelectric Smoke Detector

System Sensor D4120 4 Wire Photoelectric Duct Smoke Detector

System Sensor D4120W 4-Wire Photoelectric Duct Smoke Detector Watertight

System Sensor D4120 4 Wire Photoelectric Duct Smoke Detector

System Sensor 2WT-B i3 Series 2-wire Photoelectric Smoke Detector

System Sensor DUCTSD Single Sensor 4-Wire Photoelectric Smoke Detector UNTESTED*