Multifinger mechanical caliper is one of the simplest and most accurate measurement tools for the inside condition of pipe. They are mainly used to evaluate wear and corrosion. The tool is centralized with an array of fingers or feelers that reach out to the inside wall of the tubular goods under investigation.Multifinger calipers comes with many types, used to profile tubing or casing, including pump down devices, slick line devices, and electric wireline devices. Pump down and slick line devices are still available in purely mechanical versions, however, computer memory technology is becoming more common. Multifinger calipers are made with as few as 12 fingers on some tubing calipers, and up to 80 fingers or more on some casing calipers. Multifinger calipers are run as a specialty service.