Which tool is designed to measure the gap between two objects?

The feeler gauge is specifically designed to measure the gap or space between two objects. It consists of a series of thin metal blades of varying thicknesses that can be inserted into gaps to determine their size. The user can select the appropriate blade that fits into a gap snugly, which allows for precise measurements. This characteristic makes feeler gauges ideal for tasks such as setting the clearance between engine valves and measuring the thickness of materials.

In contrast, while calipers are used for measuring the dimensions of an object, including the internal and external dimensions, they are not specifically designed for measuring gaps as accurately as feeler gauges. Measurement tapes and rulers are also general measuring tools best suited for linear dimensions rather than for precise gap measurements. Therefore, feeler gauges stand out as the most accurate and suitable tool for this specific purpose of measuring gaps.