Each set contains one mouse and one matching ball. The mouse has a pouch of catnip and polyester fiberfill for shape, and the ball contains a small amount of cat nip in the polyester fiberfill.Your cats will go crazy for the organic smell of the cat nip, and will get hours of entertainment,The mouse has a jingle bell on the tail and the matching ball also has a jingle bell that your kitties will love.All of my cats absolutely love these toys! The mouse measures about 4 inches long from nose to tail, and the ball is approx. 2 inches.