In the field, a device that travels inside a pipeline to clean or inspect it is typically known as a pig. PIG is an acronym for "Pipeline Inspection Gauge". The acronym PIG came later as the nickname for "pig" originated from cleaning pigs (first designed pigs) that actually sounded like squealing or screeching pigs when they passed through the lines scraping, scrubbing and "squeegeeing" the internal surface. The name serves as common industry jargon for all pigs, both intelligent tools and cleaning tools. Pigs, in order to fit inside the pipeline, are cylindrical and are necessarily short in order to be able to negotiate bends in the pipeline. Many other short, cylindrical objects, such as propane storage tanks, are also known as pigs and it is likely that the name came from the shape of the devices. In some countries a pig is known as a "Diablo", literally translated to mean "the Devil" relating to the shuddering sound the tool would make as it passed beneath people's feet. The pigs are built to match the diameter of a pipeline and use the very product being carried to end users to transport them. Pigs have been used in pipelines for many years and have many uses. Some separate one product from another, some clean and some inspect. An MFL tool is known as an "intelligent" or "smart" inspection pig because it contains electronics and collects data real-time while travelling through the pipeline. Sophisticated electronics on board allow this tool to accurately detect features as small as 1 mm by 1 mm, dimensions of the wall of a pipeline as well as depth or thickness of wall (helps indicate potential wall loss).