These jump rings have been soldered closed. Useful as the female half of clasps or as the end ring over which you loop and crimp your beading wire. Attach the smaller clasp of your choice to the ring with an open jump ring or split ring.
14K/20 Gold-filled, which means that the outer 5% of each item is 14K Gold. This is hundreds of times thicker than electroplating, which can be measured in mere microns.