The Catit Senses 2.0 Fireball is a motion-activated illuminated ball with replaceable batteries. This circuit ball is an attractive bright orange color and lights up enticingly when put into motion. There is two LR44 batteries included. Insert the Fireball into one of the Catit Senses 2.0 Circuits for hours of entertainment for your cat! Includes 2 replaceable batteries Lights up when your cat bats the ball Great for nightly play sessions Compatible with Catit Senses 2.0 Circuits Diameter : 4 cm (2 in)