The variable rectangular adjustable flow limiter, connected to the dial, allows for presetting the maximum volumetric flow rate. This limiter restricts the flow area, creating a pressure drop that is proportional to the flow rate. By adjusting the limiter, the maximum flow rate can be set, ensuring that the valve operates within a specific range. This feature enables PICV valves to provide precise control over the flow rate, making them suitable for applications where flow rate accuracy is critical.