4mm Silver Plated Brass Round Flat Disc Coin Chain. This 4mm coin chain can be used by itself to make the perfect choker necklace, or it can be embellished to make something more elaborate. small pieces of this chain would be great to incorporate into a fun pair of earrings! The disc fits 3mm 22g Jump Rings. Sold by the foot (12 inches). This chain is made from solid brass and plated nickel free. Chain lengths of under three feet cannot be returned.