The Toddler/Children's Fin is designed to create lift through propulsion to establish a correct body position in water for the swimmer. The fin blades are constructed with a hard polyvinyl material. The foot pocket is constructed with soft polyvinyl for comfort and ease when putting on and taking off. Includes adjustable heal strap for various foot sizes. Sizes: toddler 5-9 (yellow) or children 10-12 (blue)