A pair of different Thermocouple wires ( e.g. ) Ni - Cr, Ni - Al, Iron - Constantan, Copper - Constantan, NICR - Constantan etc ( As per DIN - 43760 Standards ) is made in twin flat or round form to make Thermocouple leads being used for accurate temp. measuring and controls. The wires may be designed and manufactured as per customers specific requirements.