To be able to reliably connect a thermowire to a measuring device, connectors are used in most cases. To ensure no distortion of the measuring value, the wire materials of the thermocouple are also used in the connector. This means that the thermal voltage arises only at the transition to the measuring device contacts and can be measured directly there. To be able to assign the connectors to the respective thermocouple type, each has a specific colour. The colour not only indicates what type of connector it is, but also which temperature range the connector can be used in. There are various connector designs available, depending on the device and application.