They are intended for direct products checking or for their locking into the measuring equipment. The products are assembled into them to the pre-defined or agreed fixation points, like during assembling into a real unit. Quick clamping devices are used with pre-set clamping force for position locking. Then the dimension checking takes place at pre-defined points, either by the help of calibrated timing gauge or by measuring equipment directly, during which the actual position of the control master jig is measured first , and then the actual position of the product is checked.