The following should get anyone unfamiliar with Nitrox or confused by the terminology to a point where they can follow a discussion on the topic. It can also serve as a starting point for those looking to learn about Nitrox. The biggest question is "What is Nitrox?" Well, the air we breathe is Nitrox. Air is mainly composed of two gases: nitrogen (79%) and oxygen (21%), and there are some trace gases that are also found in the air, they exist in such small quantities that we can ignore them. Nitrox is also referred to as "enriched air" or air enriched with oxygen so that it contains more than 21% oxygen - usually 22% to 40% - mixtures that are usually used in recreational non-decompression diving. But in reality, Nitrox refers to any nitrogen-oxygen gas mixture, including mixtures that contain less oxygen than air. For technical diving purposes, you learn to use Nitrox gas mixtures from less than 21% up to a maximum of 100%, although richer mixtures are usually used only for decompression. Although enriched air Nitrox is relatively new to recreational diving, military and research divers have been using it to extend no-decompression limits for over 50 years. In fact, the first recorded enriched air mix was recorded by Draeger as early as 1917. The U.S. Navy and British Royal Navy studied and used enriched air in the 1940s, and the U.S. Oceanic and Atmospheric Administration ( NOAA) has more than 20 years of field experience with enriched air used by research divers. There's also the question of what you call a Nitrox mixture. To distinguish one Nitrox blend from another, the diving community uses the abbreviation EANx (for "Enriched Air Nitrox") followed by the percentage of oxygen content. For example EANx36 is a Nitrox mixture that contains 36% oxygen and the rest (64%) nitrogen: you would read "EANx36" as "Enriched Air 36" or "Enriched Air Nitrox 36" if you said it out loud. The two most common mixes used in recreational diving are EANx32 and EANx36. Why do you want to use Nitrox? You can stay underwater longer! The main application of Nitrox is that divers use it to extend the no-decompression limit beyond the normal no-decompression limits of air. Nitrogen dissolves in your body as you breathe air under pressure. The longer and deeper you dive, the more nitrogen you absorb.