Superman & Supergirl Beware! This hand-crafted necklace with a mini jar of Kryptonite may cause adverse effects! Perhaps your are a Super Villian looking to ward off Super Beings, perhaps you are Team Batman in the Batman vs. Superman Debate, or just looking for a souvenir from a long lost planet. The necklace is a glass jar hanging from a 14" chain, and should be a perfect addition to your wardrobe!