Set includes medium Carrie seat with a tray and footrest and mobile activity base. Base raises the height of the Carrie Seat so the child can interact with peers and perform many activities. Activity Base can be used only with the Preschool and Elementary Carrie seats. Carrie Activity Base features: Rear wheels to make moving easy, Seamless covering, impervious to fluids and easy to clean, Raises Carrie Seat 14-1/2" from floor.