(Pack of 20) Brass (Cast) Round Rings (Circular Rings) Outer Diameter: 14mm x Inner Diameter 9mm Thickness 2.5mm Gold Brass Brass "Round Rings" made of brass (brass) Very convenient as a connector (joint part) for keychains, wallet chains, etc. Material: Brass (cast) Outer Diameter: 14mm x Inner Diameter 9mm Thickness: 2.5mm Since it is not brazed, it can be opened and closed using tools such as pliers.