This is a set of toy cars and a Shinkansen (bullet train) that changes color in the bath with hot water. I've played with it about a dozen times, but there are no major scratches. (Quote) A set of amazing toy cars and rails that change color repeatedly with bath water and ice water. When you turn the handle, the Shinkansen (Hayabusa, Doctor Yellow) runs on the bath rails, and it changes color when it passes through the ice water tunnel. No batteries required, and you can play with it in the bath or in your room.