PTH hole copper (ETP Probe) 

Technology data for ETP Probe:

Accuracy: ±0.01mil(0.25um)<1mil(25um)

Resolution: 0.01mils(0.25um)

Eddy Current：comply with ASTM E37696 standard regulation

Testing thickness range: 0.08-4.0mils (2-102um)

Min hole dia: 35mils(899um)

Hole dia range: 0.899mm-3.0mm

The Hitachi CMI500 ETP Probe and Oxford CMI700 ETP Probe are same one , it's 100% original PTH hole probe for Oxford and Hitachi guage. 

The hole wall Cu thickness of PTH hole is measured by eddy current measurement technology. The Hitachi ETP probe adopts a unique temperature compensation technology, which is not affected by the temperature of the circuit board. At the same time, it is not affected by the inner layer of the board, double-layer board, multi-layer board, and even in the case of tin or tin/lead protective layer. The electromagnetic wave is released by the probe during measurement. When the magnetic field cuts the metal layer, the magnetic field changes, and the copper thickness of the hole wall is calculated by calculating this change.