The AM1210 Reference Standard Type S Thermocouple is made from reference grade platinum and platinum-rhodium alloy. It covers a temperature range from 0°C to 1300°C with a short term stability of <0.2°C all the way to the Freezing Point of Copper (1084.62°C). It is commonly used as a reference standard to calibrate industrial thermocouples. 
All thermocouple wires and parts are specially cleaned and annealed before assembly. Every AM1210 thermocouple is fully annealed and tested again after assembly to meet the tolerance criteria as specified below:
E(tCu)=10.575 ±0.015 
E(tAl)=5.860+0.37(E(tCu)-10.575) ±0.005 
E(tZn)=3.447+0.18(E(tCu)-10.575) ±0.005