Dataset coming from type 3 non uniqueness investigation at INRiM, for project Real-K. The dataset has been collected by 5 test HT-SPRTs, inserted into a sodium heat pipe, calibrated at the fixed points of water, tin, zinc, silver and aluminium. The measurements have been performed at 760, 780, 800, 820, 840 and 860 °C. RPTW_Polito.xlsx are measurements taken on 6 probes at the triple point of water. MAP-HP-SODIO.txt contains measurements performed with 2 reference sensors in order to evaluate the uniformity among the HP wells. note-durante.xlsx contains notes taken during the "MAP-HP-SODIO" measurements 760-SODI-2.txt contains the actual measurements of the 5 probes + 1 control probe (in channel 4). calibrations_2023.xlsx contains the calibration measurements and calculations of the test HT-SPRTs