The Unscooter Slider U4 Three-Wheeled Action Scooter (4-Inch Wheels) High quality tubular steel construction. The stability of three 4" Polyurethane wheels and the safety of dual handbrakes. Ages 3 & up. Great for building a toddler's leg and body coordination & balance. Takes a little coaching but exhilarating for both the parent and the child once they get it