To obtain accurate measurement data, you will first need to check the instrument for accuracy and serviceability. To check the accuracy, special reference samples are used, but in order to find out the accuracy of the device with their help, you must be able to read on the scale of a caliper. Before using the meter, it is important to make sure that it is in good working order, which will allow you to take the results with a low error. To do this, it is necessary to visually inspect the jaws and scales of the instrument. The presence of defects on the jaws is unacceptable, as this will lead to the fact that the instrument will show inaccurate results.