Adjustable and comes in 3 sizes: Ring Size 4-7, 7-10, and 10-13. Please REMEMBER that this is the ring size for your INDEX FINGER, not your Ring Finger so the size will probably be larger. Made with Non-Tarnish Aluminum Wire. It is Light-weight, Nickel Free, Won't turn your skin colors, and is bendable without breaking. an be used for Knitters or Crocheters. Makes a great gift for any yarn crafter! The Yarn Tension Ring is available in 20 colors!