This simply design 18K white gold filled Round box chain necklace is 18 inches long and fastens with a lobster clasp. The chain is approximately 2mm wide. This necklace is hypoallergenic and waterproof, so you can do your daily routine without having to take it off. We have 18/20/22/24/26/28 inches in stock for this model.*** Free Velvet Gift Pouch Included.