Rectangular wooden block with round ivory feet on the corner of the two main faces (two feet missing) and two wooden pinhole sights on the top edge.
On one side is an horary quadrant for Italian hours with hour lines 9 to 24, crossed by solar altitude lines originating at the zodiac or date positions for whole-hour dawn times. To one side of these lines is a straight scale of zodiac constellation names and months from June to December, divided to one third of a month; to the other side is a corresponding curved scale from December to June, not divided further. The extremity of the projection on the latter side is marked: 'LINEA MERIDIANA'. Outside the projection is an altitude scale 0 to 90, divided to 10, subdivided to 5 and to 1, numbered by 5; the apex has a pivoted brass suspension for a plumb-line (missing). The instrument is marked, 'QVADRANS HORARVM ? AD LAT GRAD ? XLIII ? MIN ? XXX ? M D L VIII', and carries the motto, 'SOLI DEO GLORIA'.
To the left of the dial is the advice '(in red) LINEAE RVBEAE ANTE MERIDIEM (then in black) NIGRAE VERO POST'. Although the colour is no longer very clear, the ante-meridian lines have indeed been filled in red. Beneath this advice is the signature: 'MINIAS PITT? FLO? FACI?'.
On the same side are two circular scales. One is a zodiac / calendar scale marked 'ROTA GRADI SOLSOLARIS', with zodiacal signs and entry dates; the first point of Aries is 19 March. This circle is enclosed in a shadow square, utilising the same plumb-line suspension as the quadrant, with scales on two sides 0 to 12 to 0, divided to 3, subdivided to 1, numbered by 3. The second circular scale is of golden numbers ('AVR NVM') and epacts ('EPACTA), and is marked 'HAEC ROTA COEPIT 1558').
Around the rim is a quotation from Ovid, 'TEMPORA LABVNTVR TACITISQVE SENESCIMVS ANNIS ET FVGIVNT FRENO NON REMORANTE DIES'
On the other side is a Regiomontanus-type altitude sundial, using the same pair of sights. An articulated shaped brass arm with one screw pivot and two rivet joints moves the suspension point of a plumb-line (missing) across a triangular grid patters of horizontal lines of a latitude scale 0 to 66, divided (10 to 66) to 5, subdivided to 1, numbered by 5, and converging lines from a zodiacal scale marked with the names of the constellations, divided to each sign, subdivided to 10 degrees. On one side is a solar declination scale, marked with the zodiacal symbols, marked 'ZODIACVS GENERALIS'. The vertical hour-lines beneath the grid are numbered  to 12 (marked 'HORAE ANTE MERIDIEM') and 12 to  ('HORAE POST MERIDIEM'). One extremity of the hour lines is marked 'MEDIVM NOCTIS', the other 'MERIDIANVS'.
The sundial is marked and signed: 'HOROLOGIUM SOLARE RECTILINEVM QDADRANGVLARE ? VNIVERSO ORBI DESERVIENS ? PER MINI ? PITTVM MON? OLI? FABREFAC? M D LIII [sic?]?'.