System Sensor 2WTA-B This i3 is like the System Sensor 2W-B with a sounder base. Brand System SensorModel 2WTA-BManufacturer System SensorType Smoke Detector (Photoelectric, 2-wire)
Simplex 4904-9137 Category : SimplexThis is, in fact, a Simplex 4904-9137. It’s just missing its housing.