Drop your colorful Water Marbles in a cup of water and watch in shock as they grow over 200 times in size. In a matter of hours, you will have hundreds of beautiful, full-size Water Marbles. The warmer the water, the faster they hydrate. Throw them, roll them, bounce them, and catch them. Enjoy the hot colors and the unique patterns. Water Marbles are slippery, slick and cool. Water Marbles are non-toxic, and safe for ages 3 and up.