Compensation wire is the proper temperature range including room temperature (typically -20 to 200 °C), has connected to the thermocouple thermoelectric properties of a pair of mutually insulated conductors, its role is to compensate for thermoelectric even terminal to display the temperature difference between the potential in the control instruments. Compensation divided into extension and compensation-type conductor wire core material is divided into common type and heat-resistant, according to temperature compensation precision divided into ordinary class and precision

F4 high temperature line