Image Number 2 for United States Patent #4530498.
First and second pads are connected by a member which is wider at the bottom than at the top. Each pad has a ground engaging element associated therewith. A generally semi-spherical bearing is provided between each ground engaging element and its associated pad so that the pads may tilt and/or rotate relative to their ground engaging element. A removable insert is provided for limiting maneuverability and thereby facilitating ease of maintaining balance by beginners.