The first stage is the part that is attached directly to the air tank. It brings the pressure inside the tank from to an intermediary pressure, but not to a breathable pressure. The second stage now completes the step down, from intermediary pressure to a pressure that is equal to the surrounding. The more common regulators are downstream ones. The pilot valves are much easier to breathe, but along with that, a higher price and more complicated maintenance.
Most regulators are right-handed ones.
Left-handed second stages are not so common. All rights reserved. Website is created and designed by Dennis Wong , 2000.