Our Tube necklace is available in three different adjustable lengths: 16.0 - 18.0", 18.0 - 20.0", or 20.0 - 22.0". The model is wearing the most popular 18-20" length at the longest setting. The circular tube pendant piece measures 5mm by 5mm. Materials: 14k gold, 14k gold-fill (14k gold over brass core/no nickel) or sterling silver (.925). All materials are hypoallergenic. This necklace was designed for Design Lab's second capsule collection in Asbury Park and is handmade in our Upstate New York production studio. Please allow 2-3 weeks to receive your jewelry as everything is made to order.