lightweight support, adjustable comfofrt. the nike flex experience 3 infant/toddler girls' shoe features a sandwich mesh upper with leather and synthetic leather overlays for breathability and durable support. an adjustable strap offers a great fit and easy on and off.. benefits. sandwich mesh upper with leather and synthetic leather overlays for breathability and durable support. adjustable velcro ® brand fastener strap and elastic laces for easy on and off and a locked-down fit. phylon midsole for flexible, lightweight cushioning. rubber outsole with flex grooves for traction and flexibility.