moved into contact with the test specimen displacement of the frame 3 releases the stop bolts 17 and 18 so that the probes 14 become free to move in the measurement direction x and also have freedom of movement to allow spatial compensation of movements of the test specimen in the x y plane the probes 14 are clamped at their bases in the block 2 by the clamp mechanism 20 fig4 also attached to block 2 but on the opposite side are two pairs of tubes 21 that support the sensor 22 with counter plate 9 the whole measurement system including the probes 14 the gimbal suspension and the sensor 22 is so constructed that a movement of the probe tips in the x y plane causes a corresponding deflection of the sensor 22 but in the opposite direction of movement however a signal representing a measured extension is generated only when the distance between the tips of the probes changes expressly included in the invention are embodiments with more than two probes 14 for example with four measurement probes and two sensors 22 offset by 90 u00b0 for the simultaneous measurement of extension in the x and the y direction a simplified design for two dimensional extension measurement can also be implemented by a system with two probes in which two sensors 22 are offset from one another by an angle preferably 90 u00b0 analogously measurement in the z direction is possible by means of a third sensor 22 for the measurement system in accordance with the invention to be employed at high temperatures effective cooling is required and is implemented as follows through one of the two external connections 24 fig4 the coolant preferably.