• Choose 316L Surgical Steel or 22k Yellow gold plated 316L Surgical Steel • Ball backs measure 3mm • Synthetic Opals measure 2mm or 3mm • Post length measures 1/4' (6mm) and is 18g • Thoughtfully packaged & ready for gift giving! • Handmade, just for you, in our sunny California Studio • Our 365 Guarantee: Our jewelry is guaranteed for 1 year after purchase date against defects. • Your earrings are sent in our gloss white jewelry box & our signature "Studio Blue" satin drawstring pouch, (shown in the last photo).