This Surgical Stainless Steel Chain features a Flat Anchor Link design. Surgical Stainless Steel is a hypo-allergenic metal which is perfect for anyone who suffers from allergies to nickel. Although all Surgical Stainless Steel contains nickel in trace amounts, the nickel is stabilized with the Stainless Steel and is considered to be safe for anyone who may have nickel allergies. Our products are made from high grade #316 or #430 Surgical Stainless Steel and meet the Mayo Clinic recommendations as well as the EU Nickel Directive. Surgical Stainless Steel is a great metal for jewelry making as it never tarnishes.Surgical Stainless SteelSize: 4mmWire thickness: 21 gaugeHypo AllergenicStyle: Flat Anchor Link