Abstract: Disclosed herein is an in-line inspection system for providing recorded measurements of internal deviations of pipeline walls. It is particularly adapted for use with pipelines carrying gas or liquid (fluids) to diagnose pipeline defects including partial obstructions by dents, out-of-round portions, or valves which reduce the available cross section and carrying capacity of the line as well as restrict the insertion of other in-line inspection technologies. Moreover, certain embodiments are light, maneuverable, and designed to be useable by any individual to obtain immediate results. Such embodiments offer new business models for providing inspection services and should result in sharply reduced inspection costs.