The Professional Scuba Association International's (PSAI) Extended Range Nitrox Diver course is designed for those divers who wish to conduct dives beyond 45 meters (150 feet) but not exceeding 55 meters (180 feet), using staged decompression techniques for both depth and extended bottom times. This course uses air as the primary back gas and nitrox as decompression gas(es). It is highly recommended the Extended Range Nitrox Diver candidates also take Narcosis Management - Level IV in order to expand and enhance their knowledge, skills and training.

The Professional Scuba Association International's (PSAI) Trimix Diver courses are designed for those divers who wish to conduct dives using helium based bottom mixes with associated advanced staged decompression techniques. The PSAI Mixed Gas diver program is conducted in three phases leading to dive depths of up to 100 meters (330 feet). These courses consist of:

Trimix Fundamentals - Level 1: Depth 55 meters (180 feet).

Expedition Trimix - Level 2: 75 meters (245 feet).

Explorer Trimix - Level 3: 100 meters (330 feet).

The Professional Scuba Association International's Advanced Nitrox Diver course is designed for those divers who wish to utilize enriched air (Nitrox) at oxygen concentrations up to and including 100% by volume (EAN22 to Oxygen) in their diving activities, including stage decompression procedures. It is highly recommended the Advanced Nitrox Diver candidates also take Narcosis Management - Level III in order to expand and enhance their knowledge, skills, training, and to prepare them for required decompression stops.

The Advanced Nitrox Manual is the text-book literary assistant to the TDI Advanced Nitrox certification course. This TDI course will help develop the mindset and practical skills necessary to optimize Nitrox breathing mixtures for divers.

After completing the course, participants will be able to make choices based on operational and logistical concerns in order to best suit their mission parameters and personal needs. The Advanced Nitrox course is the first step in taking scuba beyond the usual sport-diving applications.

The Advanced Trimix Manual is the text-book literary assistant to the TDI Advanced Trimix certification course. This course has been designed to help teach participants how to conduct serious divers well beyond the limits familiar to the vast majority of divers. Graduates from the TDI Advanced Trimix course will have the ability to plan and lead complex trimix decompression dives to a maximum depth of 100m/330 feet.

The Decompression Procedures Manual is the text-book literary assistant to the TDI Decompression Procedures certification course. TDI has brought this course to the recreational diver in response to the demand and desire for more information. The Decompression Procedures course is available to two classes of divers.

Recreational divers can take the course to develop new skills and understanding. Recreational-Technical divers can take the course during the series of courses available through TDI, usually between Advanced Nitrox and Extended Range and Trimix.

The Extended Range and Trimix Manual is the text-book literary assistant to the TDI Extended Range and Trimix certification course. Extended Range diving is exploring the limits of up to 180 FSW (55MSW) for air as a bottom mix and up to 200 FSW (60 MSW) for basic trimix. Within this range, the diver can explore many additional sights that are beyond the standard recreational Open Water limit of 130 FSW (40 MSW).With the Extended Range course behind them, a diver will be properly equipped to evaluate and plan dives where some of the less frequently visited wrecks lie, some potentially rare fish can be sighted, as well as interesting geological features.

The Nitrox Manual is the text-book literary assistant to the TDI Nitrox certification course. In many respects, nitrox is just a tool that can make your diving more enjoyable. Similar to an additional piece of equipment, once you have completed this TDI course and logged your first few nitrox dives, you will understand what a valuable tool it is. Nitrox will add useful options and flexibility to your dive planning and execution.