There are two types of scuba sets. One is open circuit and the other one is closed circuit or semi closed circuit. The major difference between them is that, in open circuit the diver breathes in from the set, and out to the waste. It is simple and cheap. While in closed circuit/ semi closed circuit, the diver breathes in from the set, and also back into the set where the exhausted air is reprocessed to breathe again. Scuba is the very first apparatus which is used by the new divers. It allows coming closer to various marine life. It not only satisfies the needs of commercial divers and researchers, but also gives a relaxing and wonderful activity to an interested common person. It also enhances the efficiency of naval researches.

Scuba diving has a number of classes. For example, commercial scuba diving, military scuba diving, media scuba diving, and police scuba diving. Commercial Scuba Diving is a type of diving where the diver is paid for his work. There are a number of branches of commercial-diving. The most well known branch of commercial scuba diving is probably professional diving. Any person desiring to become a commercial diver, usually necessitates specific training that suits legislation, such as that set by the United Kingdom Health and Safety Executive. Due to the unsafe nature of some commercial diving regulations, specific equipment is often necessary by the law. There are a number of scuba diving schools that are offering different kind of scuba diving trainings.