Which of the following describes a borescope?

A borescope is an optical device specifically designed to visually inspect areas that are not easily accessible, often used in various industries including mold assessment and remediation. This device typically consists of a flexible or rigid tube with an optical system at one end to capture images and possibly a light source to illuminate the area being inspected. This allows inspectors to assess conditions within walls, ducts, piping, or other concealed spaces without invasive procedures.

In the context of mold inspection, a borescope can be particularly valuable for identifying hidden mold growth in locations that are otherwise difficult to reach, ensuring that thorough evaluations can be conducted without causing damage to structures. This ability to visualize internal surfaces makes the borescope an essential tool in the mold specialist's toolkit.

The other options do not accurately describe the function of a borescope. Measuring air quality, outdoor filming, and measuring temperature are tasks suited to other specialized instruments which do not provide the visual inspection capabilities that a borescope offers.