For a faucet aerator to save water, the flow rate must be regulated. There are various technical means of achieving this.

In this simple application, the flow is limited through the size of the flow bore so that it precisely corresponds to a set value for a certain pressure range (e.g., 3 bar / 43.5 psi).
Neoperl refers to the products used for this as "flow restrictors". Flow restrictors have a low flow rate at low pressure, while at high pressure the flow rate is often higher than necessary.

PCA faucet aerators are equipped with an integral flow regulator. The pressure-balancing o-ring helps to achieve an almost constant flow rate regardless of possible pressure fluctuations.
In addition to the water-saving effect, a constant flow rate allows water to be distributed evenly across multiple draw-off points and complies with standards in many markets now.

DUAL CORE (DC) technology is an enhancement of the proven PCA technology. The operating principle is the same. The difference: concentric flow regulators work in parallel.
What are the benefits of this?
In the event of severe water reduction, temperature fluctuations may occur as a result of pressure fluctuations, depending on the type of mixer faucet and sanitary system. In these circumstances, please select a higher flow rate category.