Although unsigned, this unusually large instrument has been attributed to Gualterus Arsenius. The combination of a square simple theodolite and a sundial whose hour lines are marked on a revolving disc is to the same design as a signed instrument presently in the W?rttembergisches Landesmuseum in Stuttgart. The same type of theodolite, though without the sundial, is also found in an instrument by another Flemish maker Petrus ab Aggere(Epact 29051).
The reverse is divided and graduated as a quadrant but cannot now be used since a socket for a post and two suspension rings have been attached.
