Built-in sensitivity trigger, will make a simulated animal sound when the cat's paw touching the toy lightly.It is easy to draw your cats attentions.Light weight,easy to carry for indoor and outdoor activities.to have a great fun when playing with your cats. The cat interactive toys were battery built in it,50*50mm it can make 3 lifelike animal sounds as frog, cricket and bird chirping sound; the animal sounds occur when your cats touching scratching and hitting the balls, the natural animal sounds will make your cats very happy and excited when playing with them,its like them find a new friends around them,each ball inside battery can be used 10000 times sounds on lifetime. the lid of the chirping ball can be easily removed and then you can add some catnip in it, which will make your cats pay more attention to the balls; And the ball with catnip will give much fun playing experience to your cats.a pleasure toy set to keep company with your cats. These cat hunting toys are made of high quality and durable EVA, soft and safe for cats.brightly colored to make it easier to draw your cat's attention,EVA ball is durable and not easy to bite broken by your cat. When you need to work or go out for activities, the cat will feel lonely due to the temporary lack of company. This kitty toy will become your cats best playmate, helping your cat reduce loneliness and separation anxiety. While maintaining its mental health, your cat will fall in love with these little toys.