COS (TM) DNA Double Helix Necklace - Silver Toned Matching 18-20 Inch Adjustable Chain with Lobster Clap Clasp Pendant Measures 1 1/2 x 5/8 Inch Great for Science Students or Professionals Arrives in a Gift 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!