The outer part of the upper leaf has a wind rose with 32 directions, a brass index arm, compass viewing hole and decoration of blowing faces. At the bottom of the leaf is the inscription 'HIC MARINVS COMPASSVS SEMITAM TE RRA MARIQVE OSTENDIT' ('this mariner's compass shows the path on land as well as at sea').
The inner part of the upper leaf has a pin gnomon dial showing the length of the day, marked from 8 to 16, and the declination of the sun marked by the symbols of the zodiac signs. At the top is the inscription 'IMPONE FILVM FORAMINI QVOD LOCI TVI POLUM INDICAT ET HORA HABEBITVR IN CIR CVLO QVI EODEM NVM ERO POLARI INSCRIBI TVR' ('place the string in the slot which represents the latitude of your location, and the hour is found in the circle which is inscribed with the same latitude number'). The string gnomon dial is adjustable for the latitudes 39?, 42?, 45?, 48?, 51?, 54?, 57?. At the bottom is the inscription 'ILLA CVSPIS INDI CAT INCREM ENTVM ET DECRE MENTVM [E misplaced] DIEI ET DVODECIM SIGNA' ('this tip indicates the increase and decrease of the day length and the twelve signs').
The inner part of the lower leaf has a compass with silver base (glass, ring and needle missing) decorated and engraved with directions, and a string gnomon dial indicating common hours marked from 4 to 12 to 8 for the latitudes 39?, 45?, 48?, 54? and 57? (misplaced, 42? and 51? not indicated). The latitudes are indicated by the inscription 'POLVS GRADVS' and on the borders of the leaf are numbered common hours from 4 to 12 to 8. Below the compass is a scaphe dial for Italian hours numbered from 8 to 24 and inscribed 'CANCER' and 'CABRICORNVS' [sic] and a twelve-leaf flower. Surrounding the circle, 'HORO LOGIVM [H misplaced] MAIVS' ('the large clock').
The outer part of the lower leaf has a pierced lunar volvelle inscribed 'NACHT VHR' and decorated with moon and stars. On the ivory are the names of the phases in Latin and on the border 'COMPASSVS PROPE FERRVM NON RECTE ASSIGNARE POTEST' ('the compass cannot point properly next to iron') with a motif of fleur-de-lis and six-leaf flowers on the side. The four bun feet are not symmetrical, and the maker's mark (a serpent) and initials (H D) are punched on the bottom right of the leaf. A mark '8' is punched next to the edge.
See P. Gouk, The Ivory Sundials of Nuremberg 1500-1700 (Cambridge, 1988).