There is an automatic water stop valve on the top of the fully dry diving snorkel.
When the entire ventilation pipe is immersed in water, the valve can be closed in time to prevent water from entering the ventilation pipe, which can effectively prevent water suffocation.
When the upper end of the diving snorkel emerges from the water, the valve pops open, allowing ventilation.
The lower end of the diving snorkel has a novel drainage device, if a small amount of water enters the tube, you can blow air to drain the water!