The instrument is composed of a comparator (analog or digital) with a level of precision of a hundredth or thousandth of a millimeter (0.01 / 0,001), mounted on a metal bar where a conical headed pin is fixed to a end of the bar.

Another similar pin is mounted on a slider on the opposite end allowing to have longitudinal excursions of a few millimeters (± 5 mm).
The movement of the pin acts on the comparator, which in turn shows the displacements in its quadrant.

The Mechanical Strain Gauge DN250-10 has been designed to resist changes in temperature and developed with the mechanical characteristics and dimensional tolerances which exclude the possibility of movements that are not those permitted guaranteeing a constant repeatability of measurements.
Through the positioning template, you can plot the points on the structure of the drill holes and the subsequent insertion of bases for measuring or strongholds (fixed to the structure).
Using the template of “calibration” can then verify the correct resetting of the comparator before the test.

The use of mechanical strain gauge allows accurate levels of approximation (0.001 mm thousandth of a millimeter) as is required in situations of distress or during the probes with flat jacks on masonry.