Anatomical arch support * Optional back strap on sizes 34, 5/6, 7/8, 9/10 * 3/4 (Toddler), 5/6 (little kid), 7/8 (Little kid) 9/10 (little kid) All of these sizes come with back straps. * 11/12, big kid 13/1 big kid, 2/3 big kid, 4/5 big kid All of these sizes come without back straps.