The KONG Naturals Crinkle Rings are specifically designed to appeal to your cat's natural hunting instincts. The crinkle sound instantly sparks curiosit - and the combination of natural fabric and catnip provide exercise and entertainment. These toys are designed to appeal to the natural stalking and hunting instincts of the indoor cat. KONG Naturals are ecologically responsible cat toys. The materials and dyes used come from natural, renewable resources.