18 pairs of silver/grey natural color Niobium ear wires. Our 20 gauge Niobium ear wires measure ¾” from top to back bottom. They are ½” from top to front loop bottom. What Is Niobium? Niobium ear wires are an excellent choice for people with metal allergies. They are an alternative to Surgical Steel & Titanium. Niobium is highly resistant to corrosion and other reactions, and is used in artificial joints, plates, pacemakers and dental implants. Niobium is a nickel free, lead free metal and is considered one of the best metals for super-sensitive skin.