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How to dive with a second stage regulator?

OPERATION

The second stage is normally connected by a hose to the intermediate pressure chamber of the first stage. This is exactly how it operates:

STAGE 1: Once the diver inhales, pressure is lowered within the second stage to become lower than the ambient water pressure.

STAGE 2: The ambient water pressure then presses onto the diaphragm membrane, moving the lever.

STAGE 3: The movement of the lever causes the opening of the inlet valve allowing air from the first stage to flow onto the second stage, and into the diver’s lungs through the mouthpiece.

STAGE 4: When the diver exhale, the pressure in the second stage exceeds the ambient water pressure, pushing out on the membrane.

STAGE 5: The membrane having moved away, the lever then returns to its normal position consequently closing the inlet valve.

STAGE 6: The increased pressure in the second-stage opens the exhaust valve, getting rid of the exhaled air.

When the diver inhale again, the exhaust valve closes and this process repeats all over.