1mm Chain Thickness with Spring Ring Clasp (3" Extender pictured)Sterling Silver .925Strong, Durable and Long-LastingPerfect for Very Fine ChainsMade in USA This sterling silver necklace extender chain is available in lengths of 1" to 6", in half inch increments. Made in USA and constructed by hand our extender is made to last. Add just the right amount of length to your favorite necklace, bracelet, anklet or any other piece of jewelry. It's perfect for your finest jewelry and the thinnest of chains. A Tiffany's necklace perhaps. Made by Nostrand Jewelry