The following description was prepared by William Gross:
Some special customs are associated with particular ceremonies as celebrated in specific places. There were a number of such customs which then expressed themselves in material objects for the execution of the custom. In Galicia, there were a number of such objects. This one is a special Sabbath ring to be worn by the wife as she blessed the candles on Erev Shabbat. Such a custom is not known from other areas. In addition to rings, there are pendants known with the same iconography.
The inscription is an excerpt of the blessing said over Shabbath candles that reads:
להדליק נר של שבת
Translation: [God commands us] to light the Sabbath candles.