We really had second thoughts about putting this product into our catalog but we had soooo much fun with this item, we could not resist. Imported from Germany, these vials contain a highly potent form of ammonium sulfide which smells like rotten eggs when released. There are several other brands on the market but this formulation is the best (no we mean worst!). We do not advocate using this product and use it at your own risk. Just let your imagination decide how.