The intelligent pig based on the magnetic flux leakage (MFL) is frequently used for inline inspection of gas and liquid transportation pipelines. The tool is capable of reliably detecting and characterizing several commonly occurring pipeline defects including metal loss due to corrosion and gouges, dents, and buckles, which tend to threaten the structural integrity of the pipeline. The defect detection and characterization capabilities of the tool are directly dependent upon the type of critical hardware components and systems selected for the tool assembly. This article discusses the key components of an advanced or high resolution MFL tool.