The KONG Naturals Crinkle Rings are designed specifically to attract the natural hunting instincts of your cat. The crinkle sound is immediately curious, and exercise and fun are provided by the combination of natural fabric and catnip. These toys were designed to cater to the indoor cat's innate stalking and hunting instincts. KONG Naturals are cat toys that are ecologically responsible. Natural, renewable resources come from the materials and dyes used.