This bronze disc dial with suspension ring has on one side a medal bust in relief, of Philip of Spain in armour with a laurel wreath, surrounded by the inscription ' ? PHILIPPVS ? D ? G ? HISP ? ET ? ANGLIA ? REX ?'.
The other side of the disc has an alidade with folding pin gnomon and hour lines engraved from 4 to 12 to 8, on the right hand side, and the initials of the names of the months on the left hand side. At the centre, top and bottom, is foliage decoration. At the centre of the plate is a sun effigy in dotted background.
The instrument is similar to two other vertical disc dials in the Museum of History of Science, Oxford.
The dial was presented by Max Rosenheim in 1897, and is described in F. A. B. Ward, A Catalogue of European Scientific Instruments in the Department of Medieval and Later Antiquities of the British Museum (London, 1981), p. 64, no.178.