Essentially, it consists of:

1)      a horizontal circle (diameter 22 cm) graduated from 0 to 360°, with divisions in ten minutes, and equipped with a double alidade with verniers allowing readings to 20 seconds;

2)      a vertical circle (diameter 14.5 cm) divided into four quadrants, each graduated from 0 to 90° with divisions of twenty minutes and equipped with a vernier allowing the reading to one minute.

The instrument is equipped with an air bubble level, it is supported by a sturdy tripod with levelling screws and can rotate around a vertical axis.
The case, with a rectangular base (18 x 18 cm), is 20 cm in height and its sides can be opened completely, while only the upper half of the back can be opened (upwards). It can be held open by a square hook.
In the centre of the cover the glass sheath protecting the fibre from which the magnetic needle is suspended is held in place by a ring.