Get the best Diving regulator air-2.

A diving regulator or demand valve is a device that reduces high pressure from an oxygen cylinder to ambient pressure for inhalation by the diver. They are used in scuba and surface supplied breathing gas systems, where two regulators will be required so one can safely breathe at any given time. The first ones developed were single hose design but modern versions have evolved into 2 independent hoses allowing divers more freedom of movement while underwater as well as being safer should both accessories malfunction although this happens very rarely due to strict quality control regulations during manufacture process