After successful completion of the class IV course, a student directly qualifies for the class III course. If some time has expired between these two, the student must have an in-date medical report. Where SCUBA was the primary form of diving on the first course, it will now form the backup system of the commercial diver on this and all the courses to follow. High pressure and low pressure gas supplies will now feed air, nitrox or tri-mix to the diver on demand, with communication masks and helmets being the norm. More emphasis is placed on handheld tools and the skills involved in using these in a wide variety of work environments, as using these tools forms the diversâ€™ primary work function. After successful completion, students can look forward to working in a wide variety of settings, namely: Diamond diving industry, civil work projects (harbor construction, dam refurbishing) and even on offshore diving projects.