According to a January 4 CNN feature story, there are more personal submarines on the market now than there have even been before. CNN cites one such submarine, the Dragon, made by Richmond, Calif.-based company DeepFlight, as an example of how lightweight composite materials are replacing traditional metals in personal submarines.

Underwater vehicles are exposed to extremely harsh environments, and the saltwater atmosphere can cause most metal-made submarines to corrode easily. However, watercraft like the Dragon have managed to address these issues by using composites, which neither rust nor corrode. According to ACMA’s CompositesLab, unique resin formulations offer protection against harsh conditions, such as caustic solutions, acidic environments, alkaline environments, oxidizing chemicals and high temperatures.

The Dragon’s pressure hull is constructed with a proprietary composite material that is specially designed to withstand the pressures of ocean diving.

CNN adds that if the Dragon’s electric power fails, or some other critical system goes sideways, it is designed to automatically float to the surface. The only limitations (other than the $1.5 million price tag) are that the submarine has a top speed of about 5 mph and can only go 400 feet underwater. Some famous owners of the Dragon include Richard Branson and Red Bull co-founder Dietrich Mateschitz.

Another personal submarine that uses composite materials is The Scubster, which is made entirely of carbon fiber and comes in models powered by pedals as well as electric motors. According to a Washington state NBC affiliate, a company called OceanGate also plans to begin offering a submarine featuring a 7-inch-thick carbon fiber hull using Boeing manufacturing technology.

Want to take a look at an underwater point of view inside the Dragon? Check out this video below: