The full name for a Muscle Tracer that is not mass-produced as a single unit in bulk, Cored MT Units are much more powerful than their counterparts and are built differently. Instead of a single set of parts being used, and different models of the MT being built, an Armored Core is built from several different interchangeable parts, to allow maximum customization by their pilots. Some Armored Cores have also been custom made, and the corporations have not reproduced their parts (with the exception of Stinger, whose AC, Vixen, received special treatment; its parts were released to the public for Ravens to purchase).