Let me start that with any diving gas that has more than 20+ oxygen by volume is considered (Nitrox) enriched air. A diver cannot dive with pure oxygen its toxic to a diver in depth. So they have to mix it with nitrox and oxygen by volume. 50% mix stops to help rid the body of absorbed nitrogen a little quicker than normal. This gas blend is called tri-mix, it has oxygen, helium and a little of nitrogen. So because of the dive, the gas mixes they inhale, they don’t suffocate or pass out. The Enriched Air (Nitrox) there is reduced nitrogen content, which it helps limit the amount of nitrogen that the body takes on. It gives a longer bottom time before they would need to either head up or starts decompression.

When you are diving you must