The Impulse 3 Flex scuba diving snorkel took our best-selling snorkel and improved upon it either further witha two-valve system. In the event a wave breaks over the dive snorkel, the patented, upper, annular valve directs water out before it reaches the mouthpiece. Any water that does get past the annular valve drains out the lower valve, while the reservoir located below the mouthpiece keeps breathing path clear of excess water. Featuring our patented Comfo-bite mouthpiece,itdoes not require thediver to clench their teeth, helping to eliminate jaw fatigue.