Part 4/Closed Bell diving This is where the real deal is. Diving over 100 meters deep. Living in saturation. Some of the highest paid workers in the world are saturation divers. If you have done your prior training with us and meet the prerequisites you are given priority queuing and pricing for this course. The ADAS Closed Bell diver (Part 4) qualification is the most advanced of the commercial diving qualifications and enables the diver to work in the construction diving industry to over 1000 ft deep using underwater tools, breathing apparatus and techniques including the use of closed bells and saturation systems. Pay rates here often exceed AUD$1500/day. CDA is the only ADAS school able to offer you this course and give you the preparation to start your career as a high paid commercial diver.