Water marbles grow up to 200 times their original size when placed in water. Watch them grow, then watch them slip, slide and bounce! Fun to squish and play with for hours. Let them dry, and they return to their previous size. Can be used again and again. You can vary the size of the marbles by experimenting with different amounts of water. Package includes 1/4 lb. of water marbles in assorted colors. For ages 4 and up.