Which component is essential for making size adjustments in piping?

The component that is essential for making size adjustments in piping is a bushing. A bushing is a fitting that allows for the transition between different diameters of piping, facilitating connections between pipes of varying sizes. This functionality is crucial in irrigation systems, where different parts may need to be connected, and size adjustments are often necessary to ensure proper flow rates and system efficiency.

Bushings can help reduce or enlarge the diameter of pipes as required, ensuring that the water travels smoothly and without obstruction throughout the irrigation system. Without bushings, it would be challenging to connect pipes of differing sizes, potentially leading to leaks or reduced system performance.

In the context of this question, the other components serve different purposes. A booster pump is used to increase water pressure in the system rather than adjust sizes. A check valve prevents backflow, ensuring water only moves in one direction. A saddle is generally used to tap into an existing pipe rather than adjust its size. Thus, while these components are vital for system operation, they do not perform the essential function of size adjustment as effectively as a bushing does.