Gold Plated Letter "K" Initial Necklace

Small solid single letter "K" on necklace chain with lobster clasp closure and extension chain. Unable to verify authenticity, but was originally advertised as hypoallergenic 18K real gold plated stainless steel when bought. K necklace 16" not including extra strand at end. Letter "K" approx 0.25" tall . Extra strand at end approx 2.25" long. Tag at end of extension strand reads "K18" on C-link chain. Excellent secondhand condition with no known flaws or defects. From a nonsmoking home.