The regulator unit operates in the following way: the gas from the gas supply passes through the filter in the connecting piece to the regulator unit's high pressure chamber.

The gas in the high pressure chamber flows up through the piston shaft to the intermediate pressure chamber (1 in the figure below). When the pressure in the intermediate pressure chamber has risen so much that it is greater than the spring force, the piston is pressed downwards against the valve seat and closes the gas dosage (2 in the figure below).

When gas is consumed by inhalation, the pressure in the intermediate pressure chamber between the springs lift the piston from the seat and the process is repeated.

The gas flows from the regulator to the bail-out breathing valve or buoyancy compensator's bladder and suit.