Scuba Diving with Enriched Air Nitrox - The PADI Enriched Air Diver course is PADI’s most popular specialty scuba diving course, and it’s easy to see why. Scuba diving with enriched air nitrox gives you more no decompression dive time. This means more time underwater, especially on repetitive scuba dives. You can typically stay down longer and get back the water sooner. No wonder many divers choose this as their very first specialty.