This ball is a magic ball that changes shape. It expands and contracts, making the ball grow and shrink from 3.5" - 4.5". The sphere is ready to use. Simply pull it apart to expand it, or you can throw it in the air and watch it turn into a sphere before your eyes, then contract to its original size. Stretch the skeletal flower ball open, and watch it open and close as a fun mesmerizing fidget toy. Not only is this ball a great way to keep hands busy in the office or classroom, but it also helps reduce stress. Use this ball for mindfulness breathing. Slowly open the ball as you take a deep breath, envisioning your lungs filling with air, then contract it as you slowly breath out. Helps you remain calm and focus. Great calm down item! This ball is also a fun toy that you can play catch with a friend or by yourself!