Silver Stainless Steel Opal Flat Back Earrings These Silver Stainless Steel Opal Flat Back Earrings are crafted from high quality 316L stainless steel. They are hypoallergenic and nickel free making them safe for sensitive skin. These earrings feature a beautiful sparkly opal and flat screw on back for all day/night comfort. The post has 20 gauge thickness which fits a standard size ear lobe piercing. The post measures approximately 6mm long and the opal measures approx 3mm. These Silver Stainless Steel Opal Flat Back Earrings are perfect for lobe, cartilage, and tragus piercings, and are great for all ages.