Manufacturer Name: System Sensor Product Number: D4120W OEM Part Number: D4120W Product Description: Nema Iv 24Vac/Dc120v Photelec Weight:3.09lbs/1401.6g The System Sensor D4120W Nema IV Photoelectric Smoke Detector is a heavy-duty smoke detector designed for harsh environments found in commercial and industrial buildings. It uses a photoelectric chamber. For an efficient an... https://www.partshnc.com/d4120w-system-sensor-nema-iv-24vacdc120v-photelec