This is a special valve meant for high-performance diving watches to accommodate the helium leaving the space inside. This space is therefore filled with helium when saturated divers spend extended periods underwater because it's under pressure. The helium needs to be liberated during decompression as any potential damage could be caused to the watch crystal or case. To prevent this, helium escape valves are inserted on automatic watches to allow helium to escape but without compromising water resistance in the watch. This new feature is the result of precise engineering. It meets all the needs of professional divers and guarantees reliability under extreme conditions.