These are the most popular specialties that divers like you choose on their way to the Master Scuba Diver rating. Enriched Air Diver: stay down longer and get back in the water sooner. Learn how to dive using Enriched Air Nitrox, PADI's most popular specialty course. Deep Diver: explore the wonders of the deep. Learn techniques for diving in the deeper ranges of 18-30 metres / 60-100 feet. Wreck Diver: learn how to explore mysterious sunken shipwrecks, planes and even automobiles. Night Diver: learn about night dive planning, equipment and navigation.