Which device is utilized to measure the depth of small holes?

Depth gauges are specifically designed tools used to measure the depth of small holes accurately. They consist of a probe or a small measuring rod that can be inserted into a hole, allowing the user to obtain precise measurements. The measurements are typically indicated on a scale, often in millimeters or inches, making them ideal for applications where precision is critical, such as in machining and mechanical work.

While calipers are versatile tools used for measuring dimensions (such as width and outside measurements), they are not specialized for measuring depths. Thick gauges, depending on the context, often relate to measuring material thickness rather than hole depth. A pipe vise is a tool used for holding pipes securely during mechanical tasks and does not serve a measuring function at all. Therefore, depth gauges are the most appropriate choice for measuring the depth of small holes due to their design and intended use.