Mineral-insulated thermocouples

According to DIN 43710 and DIN EN 60584 with compensating cable

Mineral-insulated thermocouples are made of a flexible, thin-walled sheath cable in which the thermocouple wires are embedded in compressed fire-resistant magnesium oxide. The thermal transfer between the sheath and the thermocouple enables short response times and high measuring accuracy. A compression fitting allows mineral-insulated thermocouples for hydrogen applications up to over 1000 bar.