POWERBREATHER Wave Snorkel Fresh air: Dry oxygen flows in the top &amp; Co2 is removed separately from the bottom No gurgling: no water comes in the top vents, only air. Saliva/water ease out the bottom Wave edition is full featured - includes all caps for flip turns and open water, and extended speed vents for extra choppy water US at (Triathlon) legal (unless otherwise deemed by race director) Open water swimming for freestyle, breast, butterfly and side stroke Leaks in seal to your face effect breathing Diving down is challenging with the air filled mask. Can not equalize by holding your nose when diving deeper. Difficult to remove in a hurry. CO2 mixed air danger!