Sizing for Arch Angels Children’s Insoles:XS = Toddler Shoe Size 6-7.5Small = Toddler Shoe Size 8-9.5Medium = Toddler Shoe Size 10-11.5Large = Youth Shoe Size 12-1Keep in mind that Arch Angels will take up additional space inside the shoe, and therefore it may be necessary to move up a half-size shoe to accommodate their cushioning support. Because the product is 3/4 length, Arch Angels are designed to fit comfortably into most enclosed shoesWhy Arch Angels?Arch Angels pick up where the shoe design leaves off by upgrading the insole. Arch Angels can do what even the best shoes can’t: makes kids’ feet more comfortable while enhancing natural arch development. Arch Angels uses a unique triple-layer design: cushioning foam top layer supportive inner core durable, kid-friendly foam bottom Arch Angels are constructed of durable, non-toxic materials, and are hand washable.Arch Angels contour to the developing foot, going from a low, gentle curve in the smallest size, to a higher arch that more resembles an adult foot with the largest size. Simply put, no matter what you pay for your childrens shoes, any shoe with Arch Angels inside is a better shoe!Arch Angels will fit into any enclosed shoe and can be moved from shoe to shoe to provide uninterrupted support.