Reference metal for accurate calibration.
 This is a sample of a high purity metal (+99.9%) which is used to compensate for fluctuations in measurements caused by temperature differences, changes in the electrolyte or other influences.
 Only through regular calibrations can your   Measuring instruments   tested for full functionality, measurement deviations determined and measurement errors avoided.
 Especially when you are specifically looking for a certain metal, it is important to adjust the device to this metal. The reference metals are used for this purpose.
 When prospecting for gold, the device should also be calibrated with a pure gold reference to obtain the most accurate results.