Sigma Metalyzer PRO - Precious Metals Verifier

How does the PMV PRO work? Can the Precious Metal Verifier PRO read through plastic bags, cases, and slabs?
The PMV PRO measures a coin or metal bar that is placed between two sensors. A signal measures the surface of the sample and then sends another signal completely through the sample. The signal passing through the sample is detected on the other side. In this way, we can measure the resistivity (or conductivity) of the metal. Using the two sensors we can also determine the thickness of the sample.

The PMV PRO signal sees plastic as being invisible and therefore the plastic has no effect on the reading.

Sensors
The large sensor on the unit can measure samples that are between 1.5 to 12.5 mm thick (2.5 mm minimum for platinum, palladium and gold alloys), and at least 32 mm in width or diameter.

The small sensor is used for samples that are between .6 mm to 3.5 mm thick, and as least 15 mm in width or diameter.

Items thicker than 12.5 mm will need to use the Refiners wand and cannot make the thru measurement, only the standard surface measurement. The Refiners wand will detect tungsten under the surface of gold at a depth of 2.5 mm on each side of the sample.

Items too small for the small sensor can be measured using the Small wand which can measure items as thin as .4 mm in gold or silver, and .6 mm for platinum, palladium, and gold alloys. it has a sensor spot size of 8 mm.

What is the difference between the two bars on the display? What does the number next to the displayed image mean?
The top bar measures just the surface of the bar a fraction of a mm deep. Even so, this is deep enough to look under hundreds of plating thicknesses. The bottom bar is the thru measurement that goes completely through the sample and can detect any deeply buried counterfeit metals. The number on the display is the characteristic resistance (resistivity) in micro-ohm cm. Using the setup screen on the unit users can change the display to show the number is a different manner, characteristic conductance (conductivity), in microSiemens per cm.