Preschoolers and beginning writers can learn and play with these Melissa & Doug On The Go Water Wow! Splash Cards-Shapes, Numbers & Colors. Each of these coloring flashcards features a number, shape or color, along with a water-activated illustration. The set also includes a chunky, easy-to-grasp water pen, which can be used to color the cards. The illustrations turn white on drying, which makes them reusable for repeated on-the-go fun. Conforms to ASTM D-4236.