This necklace is built using European 4-1 weave. It is made with anodized aluminum rings. The rings contain no nickel, lead or zinc and are hypoallergenic. They will not rust, oxidize or discolor your skin and the rubber gives some stretch to the piece. They are bright, colorful and light weight. If you choose a secondary color option please leave me a note in the special instructions to seller section telling me the secondary color that you would like. The standard length of our necklaces are 18", if you require a different length again just leave me a note and we will make sure it is the correct length.