Tracer inline skates adjust up to 3 sizes to keep up with growing feet. Small adjusts from size 12J to 1, and Medium adjusts from 2 to 5.These inline skates for kids are easy to put on and take off, so children of all ages can get rolling easily. Good ankle support, important for beginning skaters. The Comfort Fit liner is washable to help keep skates fresh. Urethane wheels have the right grip and bounce for rinks, floors, sidewalks, or pavement. Size small has 64mm wheels, while the mediums include 70mm wheels. They are loaded with smooth rolling GForce carbon bearings.