Which tool would you use for measuring the thickness of small openings?

Thickness gauges are specifically designed for measuring the thickness of materials, making them the ideal tool for assessing the thickness of small openings. These gauges can provide precise measurements in narrow spaces where traditional measuring tools might struggle to fit or deliver accurate readings. Thickness gauges are often used in various applications, including inspecting metals, plastics, and other materials, and are particularly effective in scenarios requiring dimensional control in confined areas.

Calipers, while they can also measure thickness, are generally more versatile for larger measurements and may not be as precise in very small openings compared to thickness gauges. Depth gauges are tailored for measuring how deep a hole or recess is rather than thickness, and C-clamps are used for clamping and holding objects together rather than measuring thickness at all. Thus, thickness gauges stand out as the most appropriate tool for this specific measurement task.