Simplex 4904-9137 This is, in fact, a Simplex 4904-9137. It’s just missing its housing. Brand SimplexModel 4904-9137Manufacturer SimplexType Alarm (Strobe)
Wheelock MB-G10-24-R Category : WheelockI’m missing this unit’s label, so that model number is only a guess. It’s probably right though.
System Sensor PA400B+PS24LO Category : System SensorThe horn’s model is PA400B, the strobe’s model is PS24LO.
RSG RMS-1T Category : RSGEither this is an early generation RSG T-Bar or some unique variant of the more common RSG RJRMS-1T-KL.