The middle vent contains a baffle system that channels water from the barrel and discharges it out of the middle vent.
The vent located near the mouthpiece allows any small amount of water that might have reached this point to vent out its one way valve.
This is a very unique, dry snorkel! There are three vents in the SEASOFT TRI-GEMINI™ Snorkel and water rarely, if ever, reaches your mouth. The inverted vent at the top blocks the entry of most water and the liquid that does rarely enter is forced by air pressure in the barrel to the sides of the barrel. This water is then channeled down a baffle system and discharged out the middle vent located just below the top. This middle vent's baffle expels the water while it allows air to flow to the mouthpiece. As a further precaution, a third vent is located at the bottom of the snorkel. Bottom line, the SEASOFT TRI-GEMINI™ Snorkel is a breakthrough in snorkel design with incredible, dry performance while being lightweight, low drag and intuitive to use.