Video from @batuhanganiz, with xtar D26 1600 dive light. "Underwater communication using dive lights is crucial. Night dives, dives with limited visibility, deep dives, and cave dives are situations where we don’t want to be without our lights. Therefore, we use dive lights not only to see but also to communicate. Especially during dives where you move in a single file in a confined area, it’s important to be aware of the signals so you don’t miss a “Problem” signal from the person behind you."