What type of measurement is a feeler gauge specifically designed for?

A feeler gauge is specifically designed for measuring thickness, which is its primary function. This tool consists of a series of metal blades of varying thickness, which can be inserted into gaps or spaces to determine the exact measurement of the gap. This is critical in various applications, particularly in machinery and engine assembly, where precision is vital to ensure proper clearances between components. Accurate thickness measurement helps in maintaining the performance and efficiency of machinery.

In contrast, the other types of measurements listed don't correspond with the function of a feeler gauge. Length measurement typically involves tools like rulers or calipers. Pressure measurement uses devices like manometers or pressure gauges, while temperature measurement requires thermometers or temperature sensors. Thus, the role of the feeler gauge is uniquely suited to measuring thickness, making it an essential tool for specific applications in pipe fitting and engineering contexts.