Zeiss introduced the Model Ni2 Automatic Universal Level in 1951, with advertisements and articles in scientific journals and exhibitions at meetings of surveyors and geodesists. Terming the Ni2 a level of "radically new design," Zeiss noted that it was "the first 'automatic' level built in large quantities," and explained that its "ingenious compensating device automatically levels the line of sight with an accuracy of ± 0.3 seconds of arc." The Ni2 was a remarkably successful instrument. A Zeiss advertisement of 1970 boasted that the company had produced over 50,000 levels of this sort in the past 20 years. The Michael Baker Corporation purchased this example new in 1961, and gave it to the Smithsonian in 1997. It was made in the Zeiss factory in Oberkochen, in the Federal Republic of Germany.
Ref: C. L. Peckinpaugh, Jr., "The Zeiss Opton Ni-2 Automatic Level," Surveying and Mapping 14 (1954): 185-191.
Carl Zeiss, Level Ni2.