This simulator is designed to generate slowly increasing and decreasing brightness of two alternating LEDs. The effect is timed to accurately represent the slowly rotating beacon in a lighthouse with a higher intensity white light followed by a lower intensity green light (rear of beacon). 

The N8035A version is for a single white LED (flashing twice as often to achieve the same rotational timing effect).

The N8035B is intended for lighthouses that require extra light output due either to the level of ambient light in its surroundings, or for larger scale models (O or G scale). The module is configured for two LEDs to double the light output.