Our Captured Orbital Necklaces are constructed using a modified Open Round weave and anodized aluminum rings. They contain no lead or nickel and are hypoallergenic. They can be ordered in a wide variety of colors or you can contact us to do custom colors. They are made with 18 gauge 1/4" anodized aluminum rings and the standard size for these pieces is 19". If you need a different length just let us know.