Somewhere between the decidedly unrealistic TRITON human gills and the somewhat limiting Easybreath, bob Ameo's series of high-performance snorkels, the Powerbreathers. These upgraded underwater oxygen channels are intended to give casual swimmers and leisurely ocean explorers, as well as competitive athletes, a simultaneously enhanced and natural way to breathe during their subsurface pursuits.
In appearance, Powerbreathers consist of a pair of snorkels (tusks!) that connect into a respirator-like mouthpiece. Ameo has patented the configuration their Fresh Air System. Using valve technology and the second Powerbreather tube, swimmers are able to breathe in and out two different passageways (D-Tubes) so that only oxygen-rich air reaches their lungs. The tubes' ventilation system and diffusers also ensure no water can enter the snorkels. This enables users, particularly athletes, to breathe normally--and heavily--without concern that they'll suddenly suck in 4 ounces of liquid chlorine or salt water. Or have to stop over and over to clear their snorkel. Ameo says you'll even be able to do flip turns without pause.
For those (most of us, probably) who normally swim for exercise without a snorkel, the Powerbreather's offers a means of improving technique, endurance, and respiratory muscle training. In addition to breathing normally while wearing it, you'll also be able to eliminate the "head-turn" for breath, keeping a steady position in the water, and swimming with even, symmetrical strokes.
The Ameo Powerbreather pictured here is their Wave Edition, which is suitable for swimming pools and both calm and choppy open water. Contents include the Powerbreather, 2 x standard Speedvents, 2 x large Speedvents (extended for open water use), 2 x flip caps, 1 x blind cap, and a carrying case.