This small brooch is a replica of a historical example from the Baltic area during the Viking age.
These penannular brooches, also called horseshoe, omega brooches or fibulas, were used to close garments or fasten all sorts of material, but mostly fabric. The smaller brooches, like this one, were mostly used to close the neckline of tunics and dresses or to fasten leg wraps. The elegantly curled ends prevent the needle from coming loose.
The fibula measures 4 x 3 cm and has a needle of 5 cm. It is available in bronze, as well as a silver-plated version