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