Four-wheel support helps young riders practice balance, with 2 detachable training wheels forming a triangular structure that keeps the 12-in bicycle upright until kids gain confidence. The 33.5 x 19.5 x 26.5 in frame is built from solid carbon steel to handle regular use, while anti-puncture rubber tires with layered construction help maintain steady riding. A front hand brake works with a rear coaster brake so children can slow and stop in a controlled way. The adjustable handlebar and seat let you match the fit to a growing rider, and the ergonomic saddle and non-slip pedals support up to 110 lbs for ages 3-4 years old.