At both end it has strong Bolt ring clasp and there is a choice of 5 mm or 6 mm 9ct gold Bolt rings. This safety chain/necklace extender features

9ct Yellow Gold Necklace Necklet Extender Safety Chain with 2 Bolt Clasps

10K Solid Gold Chain Necklace Extender 2 Inch, Delicate Durable Adjustable Gold Chain Extender for Gold Necklace Bracelet Anklet: Clothing, Shoes & Jewelry

HOW TO USE - Keep the magnetic clasp fastened when attaching necklaces to Necklet. Start from the bottom with your longest/heaviest necklace ending with your shortest necklace on the top. When clasping the Necklet together make sure the inlaid prongs are aligned properly into the corresponding holes on the other side. You will know when they are lined up because you can hear a “click” when in place. See below a visual representation and watch video under product images for more help.

Necklet Double Layering Clasp

Chains / Longguards — Gembank1973

Package: Comes with 3pcs sterling silver necklace bracelet extenders chain（1,2,3 inches，one for each size）, easily add the length of your jewelry.

Necklace Extender White Gold Chain Extender 925 Sterling Silver Necklace Bracelet Anklet Extenders C…See more Necklace Extender White Gold Chain

14K Solid Gold Chain Necklace Extender 2 Inch, Delicate Durable Adjustable Gold Chain Extender for Gold Necklace Bracelet: Clothing, Shoes & Jewelry

Solid 925 Sterling Silver Chain Extender Safety Chain /

9ct White Gold 2 Inch Extension Piece, Use to Make Chains Longer! 0.75mm Width Chain - David Cullen Jewellers % %

Necklace Extender White Gold Chain Extender 925 Sterling Silver Necklace Bracelet Anklet Extenders Chain Extension for Jewelry Making (1 2 3 inch) : Arts, Crafts & Sewing