The flash lamp or dive flash lamp ensures that the diver can be seen in the event of a dark or dark dive.
The flashlight will also be a great help to the surface diver to get spotted boats at night.
Not all flashlights or stroboscopes are alike. All waterproof for diving, this one will be up to 50m for the simplest and up to 150m for the most evolved.
Attention also in the choice to the duration of flash light.