4 years & up. Discover the beauty of seashells inside and out! Examine 18 real x-rays of a wide range of sea shells, coral, and sea animals to see their inner structures. Look at the printed cards to see the outside structure, color, and design. Match up the x-rays to the printed cards. Lay the x-ray over the card to see how the inside and outside go together. The cards are 4" x 6". X-rays vary in size. Includes teacher guide detailing the name of each shell and activities.