Extend any necklace by up to 5 inches with this magnetic clasp extender. All Sterling, silver except the magnets and the spring inside the lobster clasp. Just attach one end of your necklace chain or ring to the lobster catch, attach the remaining chain to the clasp on your necklace at the desired length. Necklace will be easy to put on and take off with these magnetic clasps that are very strong. Easy to switch out between necklaces.