This instrument is in the shape of a polyhedron. Like other table-top dials, it is painted and embellished, and has fourteen decorated faces bearing the hour lines and their gnomons. The compass allows the instrument to be oriented correctly, allowing the time to be read from the shadows of the gnomons projected onto the hour lines.
Although the instrument is unsigned, the style in which it is decorated and constructed imply that it was made by Stefano Buonsignori, the Olivetan friar and cosmographer to the court of Francesco I de' Medici.
