KaShDa Multi-Ring 14MM Silver Plated Toggle Bar Necklace Extenders 1-13 Rings (1 5/8-12 1/8) One extender that can let you adjust the length of your necklace to the desired length. 14MM (about 1/2") Silver Plated Zinc Ring and Bar. The ring has a hole size of 11MM (just under 1/2"). The bar is 19MM (3/4") long. See IMPORTANT SIZE INFO below. 3.7MM Silver Plated Brass Core Curb Chain, just enough to allow easy insertion of the bar. The shorter sizes can be used on a bracelet or use a longer one as a bracelet.