Dan writes -
An endoscope is a thin viewing device, suitable for being poked into places where the human eye cannot, and possibly should not, otherwise see. Since it’s likely to be dark… in there, endoscopes usually have some sort of illumination device built in. The more sophisticated kinds of endoscope shoot light out of the same lens the user looks through. The common otoscope, for peering into ears, is the simplest example of that idea.
Endoscopes are useful for all sorts of things, but they’re also usually rather expensive. Endoscopes that incorporate a camera so you can hook them up to a TV or computer are, generally speaking, more expensive again.
And then, there’s this one.