Clayton Online Sales COS (TM) Serotonin Neurotransmitter Molecule Horizontal Necklace Great for biology, chemistry, or medical majors nurses and doctors Double Sided Pendant 18 Inch Matching Chain with Lobster Claw Clasp Arrives in a Gift Box 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!