20 Pressure less Tennis Balls in a re-usable mesh carry bag. Pressure-less means they never go dead, which makes them great for tennis practice, ball machines, filling up ball baskets and hoppers, or just making sure your pet has hours of fun chasing these balls. They fit Chuck-it style dog ball launchers and automatic ball launchers. Durable rubber and a premium felt ensures their use can be universal, whether your a budding tennis player or a pet owner.