Temple rings are the most characteristic part of Slavic medieval dress. They are so called because they were worn on the headband, near the temples of a woman or a girl. Most were made of base metals such as copper alloys or iron, though silver and even gold were occasionally used.

Reference: http://members.ozemail.com.au/~chrisandpeter/trmain/tr1main.html

These two are a replica of an archeological artifact from Milicz, Poland, dated 10th-12th century A.D. They are made of solid bronze and they have 3.2cm (1.25 inch) in diameter.