The information on content, theory of operation and metrological concepts of the State primary special standard of length unit in the field of measurements of deviations from straightness and flatness, GET 130-2019, conducted in 2019, is provided. The results of metrological characteristics research of the measuring interference system included in GET 130-2019 are described. With the help of an additional measuring interference system, the unit is reproduced on the basis of fundamental physical constants and the properties of matter – interference, which eliminates additional instrumental sources of errors (uncertainties). The transfer of length in the field of measurements of deviations from straightness and flatness in the range from 0 to 50 μm on the length of the measured surface up to 30 m with the highest accuracy in Russia is ensured. The conducted comparisons proved that metrological characteristics of GET 130-2019 correspond to those presented in the database of measuring capabilities of the International Bureau of Weights and Measures (BIPM) on the already confirmed by means of stationary and autonomous measuring profile length to 5 m, as well as the level of foreign standards, presented in BIPM on the length to 30 m.
