The instrument is made up of a thin, circular copper plate. The limb is divided into parts numbered from 1 to 32.
These are followed, as one approaches the centre, by the initials of the directions of the winds, in between which are triangular points of various widths, which appear in chiaroscuro because one half is smooth and the other half is milled.
The principal directions, North, East, South, West, have some inscriptions within the triangular point. East and West are depicted by a bee, North is represented by a stylised lily, South by a triangular shape.
Towards the centre of the instrument is a circle, concentric with the limb, which bears the inscription 'SIR ROBERT DUDDELY WAS THE INVENTER OF THIS INSTRUMENT, 1596'.
The central part of the instrument is occupied by a zone with four radii which are joined to a disk in which nine holes have been made at the ends of nine engraved lines which meet at the centre. A hook is fixed to the Southern point of the external rim of the instrument. A short support made of turned wood is fixed to the Northern part of the rim, on the back of the instrument. This was probably used to place the wind-rose on a stand.
See M. Miniati, Museo di Storia della scienza: Catalago (Florence, 1991).