The Trac Star Youth Adjustable Quad Skate by Roller Derby is a great adjustable skate for kids. The small size skate adjusts from size 12jr to size 2 and the medium skate adjusts from size 3 to size 6. These skates are made of molded polymer with a washable padded liner. The wheels are 54mm, made of urethane, and have G-FORCE 608ZB bearings.