The MGM250 mechanical deformation meter, also known as a removable gauge, is a measuring instrument suitable for evaluating amplitude variations (relative displacement) between two points, with order of magnitude a thousandth of a millimetre. This instrument, strong in its reliability and repeatability of measurements, is mainly applied in crack pattern monitoring operations or in deformability testing with the use of flat jacks. We can find mechanical or electronic type deformation meters, depending on the transducer which is being used for measurement.