The course objective is to introduce Tec 40 divers to the first stages of full, technical deep decompression diving. Certified Tec 45 divers are qualified to make multistop decompression dives that employ enriched air and oxygen for accelerated decompression. The expectation is that a Tec 45 diver intends to continue on in technical diving. Accordingly, the course not only develops the knowledge and skills to make open circuit technical dives as deep as 45 metres/145 feet, but also begins developing the knowledge and skills the diver will need at the Tec 50 level and beyond.