The gas with the intermediate pressure from the pressure regulator passes the dosage regulator which provides the dosage volume with gas at 3.5 to 9 bar depending on the diver's breathing activity and diving depth. The dosage regulator ensures that the diver always gets the same amount of gas in terms of weight no matter what depth the diver is at.

The dosage regulator is controlled mechanically by the motion of the bellows ensuring the dosage rate and volume are always at a fixed ratio in relation to the breathed volume.

When inhaling, the bellows are emptied of air and the bellows arm shaft in the regulator block is turned. The bellows arm shaft actuates a metal pin mechanically on the dosage regulator which is pressed in and opens the regulator filling the dosage volume with new gas. This is interrupted once inhalation stops. When exhaling, the new gas in the dosage volume is gradually transferred to the breathing circuit's inhalation side. At the next inhalation, the new gas is mixed with the purified gas.