Carl Zeiss Theo 020A theodolite. Green enamel. Three screw levelling head. Used for measuring horizontal and vertical angles in land surveying and for setting out works.
Information from Zeiss Archives [translated from German]
The total station theodolite Theo 020 is a further development of the tried and tested Theo 030; Standard instrument for all tasks of the medium level of accuracy, i.e. for polygonation above and below ground, small-scale triangulation, setting out work and topographical tachymetry.
Automatic altitude index stabilization, optical foot point plummet built into the alidade, parallax-free optical sights for rough aiming in both telescope positions, vertical circle image that can be switched off, adjustable crosshair illumination, telescope that can be penetrated on both sides. Telescope magnification 25x. Circle reading horizontally and vertically. 10cc (6″), mean error of a direction measured in two telescope faces