Although it is known as the Astronomical Ring, the full name of this instrument used for telling solar time and other astronomical measurements is the Universal Equinoctial Ring. 

This detailed replica is based on one of the most popular styles of sundials in the 17th & 18th centuries.  It is fully functional, and can be used to make astronomical measurements as well as tell the time.  Cast in solid bronze.

Diameter: 45mm / Thickness: 4mm  

Full instructional booklet included.