Titanium G23 Silver Belly Button Bar Navel Banana Ring 14g 12mm Grade 23 (G23) Titanium: A body-friendly material because its an elemental metal  it doesnt contain nickel. Titanium is a perfect choice for people with hypersensitivity. Lightweight and perfect for initial piercing. Bar length: 12mm. Balls diameter: 5mm and 6mm. FREE standard shipping US.