video borescope is a highly specialized, and sometimes very expensive,
tool which is used in the diagnosis, monitoring and tracking down
of maintenance issues.
A video borescope consists of a very small camera and light which
is mounted at the end of a long flexible shaft. The shaft can be
passed along tight passages and tubes, around corners and into areas
where the eye can't see to look for hidden problems and defects.
Video borescopes come in two types. One which comes with its own
portable and dedicated monitor (as pictured here). And another which
is just the shaft and camera, a separate video monitor must be used
to see the images.