Slippery Spheres are fun to throw, and they slip, slide, bounce and explode! To experience the ingenuity of this exciting product, simply fill a cup or bowl with water and add Slippery Spheres. In less than one day, Slippery Spheres will expand to over 200 times their size as they grow to the size of a marble! Let your imagination take over as you experiment with Slippery Spheres! Slippery Spheres are completely reusable for use over and over! Slippery Spheres are safe for ages 4 and up, non-toxic, and environmentally friendly.