18k gold plated stainless steel/silver polished stainless steel Allergy information: Hypoallergenic Length of studs: 4mm x 4mm 18k gold plated stainless steel/silver polished stainless steel Closure: 18k gold plated butterfly backs Shipped within 1-2 business days 14-day returns Waterproof | Tarnish resistant | Hypoallergenic Enjoy the elegance of 18k gold plated 316 stainless steel with the strength of medical grade 316 stainless steel. With a stainless steel chain, there's no more green discoloration on skin. Stainless steel is a metal that is very stable and does not react. Classified hypoallergenic for sensitive skin. The advantage of stainless steel over other jewelry like sterling silver is that stainless steel is a metal that does not tarnish nor corrode by chemical reaction with water or other substances like perfume or creams. It is a metal that stays shiny and doesn't require maintenance, unlike sterling silver or other gold plated jewelry.