This instrument is very similar in design to the 'geometrical gunnery instrument' published by the Zurich-based instrument maker and author Leonhard Zubler. The instrument was intended for a range of functions and, like several other 'universal instruments' of the late 16th and early 17th centuries, has a central leg to which are attached further jointed legs. By moving the slider on the main leg, the inclination of the shorter legs is altered.
The instrument includes scales for setting out polygons and measuring degrees, and scales of inches for Prague, Vienna and Rome. There is also a compass and a string gnomondial. A similar instrument, probably by Jost B?rgi, is in Florence (Epact 47019).