PlasmaCar Purple & Green - Polyurethane Wheels Special Edition No Gears , Batteries or Pedals. Just Steer and Away you Go. Now with polyurethane wheels for a smoother, faster ride Great Exercise Inside or outdoors The PlasmaCar is meant to be used on a smooth, flat, hard surface and will not function properly on carpet, grass, gravel, sand or any surface with give Multiple Award Winner