Convertible Submarine is a fun storybook for ages 3+ that can also be used as a playmat and a sit-in vehicle for toddlers. Once unfolded, parent and child can read the text, which describes an exciting journey to a shipwreck in a submarine. The bright, busy illustrations are packed with colourful details such as tropical fish and lost treasure. Laid on the floor, the book can also be used as a playmat. The boards can then be refolded into a large, sturdy submarine that a child can sit in and pretend to drive.