With a coefficient of expansion of about .0000015 per degree Centigrade, Keuffel & Esser's LO-VAR tapes were said to be more stable than ordinary steel tapes, which have a coefficient of expansion of .000016 per degree Centigrade. Keuffel & Esser also explained that, since LO-VAR tapes were intended for precise base line measurements, they generally carry only the end marks and one or two intermediate marks. This tape, however, is marked every 5 meters,
and at 12.5 and 37.5 meters. It was tested by the National Bureau of Standards, and belonged to
the United States Coast and Geodetic Survey. New, it cost $75.
Ref: Keuffel & Essser, Catalogue (New York, 1936), p. 535.