Anti-Stress Set for Dogs contains: - Anti-Stress Mixture of essential oils 5ml.- Black ceramic pendant with string. Handmade pendants are made of black ceramic. Lithuania is one of the few corners of the Earth where black pottery is preserved. It is said that black pottery is the most ecological. When ceramics are heated in a hot oven, moisture evaporates from the wet clay, leaving many small air holes. This is where the spilled essential oil comes in, which evaporates slowly, spreading the aroma and the positive effects of the essential oils.