Welded J or K thermocouple glass-silk insulated wires as per IEC 60584 standard.
Example of product description TC1J ISOL SV 7X0.2 L= 480
1 ==> number of TCs
J ==> thermocouple type
For multi-strand wires : 7x0.2 ==> no. + diameter of the strands
For single-strand wires : D=0.5 ==> wire diameter
L= 480 ==> total length