Zad Jewelry Silver Plated Serotonin Molecule Necklace on 16" Chain Unique Serotonin Molecule Pendant 16" Link Chain with 2" Extension Silver Plated Base Great Unique Gift Idea! 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!