The original development of this technique was largely directed at oil and gas production. This corrosion monitoring technique measures corrosion damage over several meters of an actual structure and provides measurements of metal loss over a pipeline surface.. An induced current is fed into the monitored section of interest and the resulting voltage distribution is measured to detect corrosion damage. An array of permanently installed pick-up pins is positioned around the outside of a pipe to produce an electric potential map of the structure. Increased pin spacing implies lower resolution for localized corrosion. Typical applications involve pin attachment to the external surface of a pipeline, to monitor corrosion damage to the inside of the pipe walls. Manufacturers quote resolutions of 1,000 ppm of wall thickness.