You cannot breathe directly out of a scuba tank because of the high pressure. A regulator reduces pressure to safe a level that can be inhaled by the diver. A diving regulator has two parts: the First Stage reduces the tank pressure and connects it to the Second Stage which contains the mouthpiece for breathing
The lightweight techno-polymer S360 is an air-balanced second stage similar to the S560 but with pre-tuned inhalation backed by a simple Venturi-Initiated Vacuum Assist (VIVA) switch for divers who prefer to keep their reg systems simple. It breathes smooth and easy.