The Borescope is a high quality optical device with its own light source and is a handy tool for the inspection of the inside of a cylinder. The Borescope is ideal for critical inspection of typically inaccessible areas.
Industries use the Borescope in many different applications and is well suited for internal inspection of pumps, pipelines, tubing and a host of other factory or field inspections. A flexible borescope is best used in areas that have obstructions and curves.

Rigid borescopes provide a superior image to a flexible borescope, but are limited to viewing the object in a straight line.
Flexible Fiber Optic Borescope Kit. Rigid borescopes give higher quality images, are easier to use and are less expensive than flexible scopes of similar quality. Both flexible and semi-rigid models are available, in lengths up to 600 in.
The flexible borescope, although a bit more fragile, offers more flexibility, which enables the user to view different angles with ease. Visual inspections can be made easy with the use of a flexible borescope.
There is plenty on information on the internet outlining the benefits of such optical equipment devices but one that springs to mind is the Borescope Information web site.