Miniatronics End of Train Warning Flasher, R (MNT10001101)
This is the End-Of-Train Flasher Red Light Model Railroad Electrical Accessory by Circuitron.
Scale size housing, easily mounted on any freight car. High-intensity LED slowly flashes a bright light rearward. Requires 3V input, easily obtained from two small batteries; the TP-1 Track Power (#800-2001), can be used if the car is equipped with track power pickups.