Passi Test is a tool designed for those who need to know exactly the real quality of the stainless steel. It consists of a “probe pen” – which will be put on the surface to be tested – containing the electrochemical system and a reading external unity. Passi Test measures the open-circuit potential and the nobility of a metal (and consequently its resistance to corrosion). The test, which is non-destructive nor damaging, is fast (the result is given in about 15 seconds) and numerical: while the other passivation tests, purely chemical, are based on the interpretation of a colour (ferrocyanide test), thus offering a strongly subjective datum, often distorted by superficial impurities, Passi Test releases an exact and not disputable numerical value. The Passi Test internal system is calibrated in such a way that the zero is the discriminating point: if the value is higher than zero, then the stainless steel is passivated, if the value is lower than zero, the passivation is either scarce or non-existent. As such, it is possible to compare different kinds of stainless steel: the higher than zero is the value, the better the passivation of the sample; the lower than zero is the value, the worse is the passivation of the tested stainless steel.