25 Rose Gold Fill open jump rings perfect for jewellery making, especially chainmaille. Saw cut and then tumbled polished for a high quality finish.Gold Fill is where a layer of gold is bonded to a base metal (usually brass). In this case, the gold layer is 14K. Copper is alloyed with gold to make the rose colour.I inspect each one by hand after tumbling to ensure the quality.The wire diameter is 0.8mm (approx AWG 20). The size option in the listing refers to the Inner Diameter of the ring (ie the size of mandrel used).