Motion-activated light-up ball with replaceable batteries. Replaceable batteries: The new Catit Senses 2.0 Fireball allows you to replace the batteries. Simply unscrew the bottom half of the Fireball and change the batteries for countless hours of fiery fun Play at night: Cats are crepuscular animals and have excellent night vision. However, even our feline companions need some light to be able to see in the dark.The Catit Senses 2.0 Fireball flashes a bright red color when your cat paws at it, lighting up the circuit as it whizzes by enticingly For use with Catit Senses 2.0 Circuits: The Fireball is a perfect fit for the Catit Senses 2.0 Circuits, which are available in 3 different models (Play,WaveandSuper) The Circuits build into 100+ different layouts, which helps keep your cat’s playtime fresh and exciting.