ASTM E 747/ASTM E 1742 Penetrameters/ IQI

Each indicator consists of a series of six parallel wires of different diameters 25 or 50 o 50mm height, mounted between two thin sheets of transparent, flexible PVC.

Lead charachters identify ASTM. It follows a number that identify type of material and a letter that define the range of wires diameters.

The other number (6/11/16/21) identify the number of wire of greatest dimeters of this set.