Silver DNA Double Helix Science Molecule Necklace Unique DNA Double Helix Necklace for Science Lover! Pendant Size: 1 1/8" x 1/8" 18 Inch Chain with Lobster Claw Clasp Arrives in a Gift Box/Bag MONEY BACK GUARANTEE - Clayton Jewelry offers a 100% money back guarantee if you don't love it! You can return this item for any reason and get a full refund: no shipping charges. The item must be returned in new and unused condition. Go to Your Orders to start the return Print the return shipping label Ship it!