I have been in every position immagineable in this wing and this is not a problem. Just competitive marketing jargon. The tank would pinch the air flow anyway, so it's not neccessary. If someone is putting that kind of air in the bag while at the bottom and has the need to maneuver, they are way overweighted to begin with. It's just not a problem. Ask anyone who has dived one.jonnythan:It's a horseshoe wing, as opposed to a donut wing. Air will flow from one side to the other only via the top of the wing, not the bottom. This can be a problem if you're horizontal or head down in the water.