Four contact points on the ground from the 12-in wheels and removable training wheels help young riders ages 3 to 4 years practice balance while staying upright. A dual brake system combines a front hand brake with a rear coaster brake so kids can choose how to slow or stop. The adjustable saddle spans 19-21.5 in to match 18-21 in inseams, and a quick release lever makes height changes simple. A solid metal frame, non-slip pedals, ergonomic seat and multi-layer rubber tires support up to 145 lbs on common paved surfaces.