This is for either a 4mm, 5mm, or 6mm, Silver Stainless Steel Miami Curb or Cuban chain necklaces from 18 inches to 24 inches. Stainless Steel will not tarnish nor discolor.Available Lengths: Recommended for best sizing to measure your length using a measuring tape or a string and then hold it against a measuring tape Recommended 18" - 20" in - Teen's/Womans Necklace 22" - 24" in - Men's NecklaceRecommended size:-We suggest Necklace lengths 18"-20" for Boys Girls and woman, and 22"-34" inch for Men.4mm and 5mm are unisex 6mm is commonly worn by men