An optical instrument consisting of an objective lens, a coherent (usually flexible) Fiber Bundle and an eyepiece to examine the output of the fiber bundle.

A fiberscope (or fiber scope, fiber optic scope) is a flexible inspection device that consist of fiber optic bundles with an eyepiece at one end, and a Lens at the other. Usually it has 2 type of bundles: fiber optic Light bundle (for illumination of objects) and fiber optic image bundle to relay image to eyepiece. The lens is often a wide-angle lens, and the eyepiece is occasionally instead connected to a camera. Fiberscopes (fiber optic scope) has some very important advantages and features such as FLEXIBILITY, higher length (then rigid borescope) and ARTICULATION capabilities. Articulation mean that inspector can manipulate a tip of the fiberscope and pass along the corners, angled tubes and hard to Reach areas as well as inspect object from different angles. There could be 1, 2 or 4 way articulation fiberscopes (fiber optic scope). Usually small diameter fiberscopes like 4mm diameter has only 2 way articulation. You will be able still to see all what you need and all angles but needed to rotate scope.
All fiberscopes (flexible borescopes) introduce a certain amount of image Distortion and depends on fiber diameter and amount of fibers in the image bundle.
It is used for inspection work, often to examine small components in tightly packed equipment, when the inspector cannot easily access the part requiring inspection.
Fiberscopes (fiber optic scopes) are used in aircraft inspection and maintenance, engines machining, computer repair, espionage, locksmithing, safecracking, and computer forensics, among many other uses.