A theodolite is an instrument used for measuring angles for surveying . It consists of sight binoculars and a protractor for determining angles, as well as small lenses. This is a portable theodolite, which was used on the Maud Expedition 1918-1925. It was one of six theodolites they had on board at departure in 1918, and a favourite of Harald Ulrik Sverdrup. This theodolite was produced by Max Hildebrand at August Lingke & Co in Freiberg, Sachsen, Germany.