M.I Cable

M.I. (Mineral Insulated) cable is used to insulate thermocouple wires from one another and from the metal sheath that surrounds them.
MI Cable has two (or four when duplex) thermocouple wires running down the middle of the tube.
The tube is then filled with magnesium oxide powder and compacted to ensure the wires are properly insulated and separated.
MI cable helps to protect the thermocouple wire from corrosion and electrical interference.