Nike Flex Experience 4 NATURAL RIDE. EVERYDAY COMFORT. The flexible and lightweight Nike Flex Experience 4 (3.5y7y) Boys' Running Shoe delivers a perfect balance of comfort and natural movement through its minimal upper design, resilient midsole and lockeddown feel. Articulated foam midsole provides a natural stride. Minimal upper design enhances flexibility. Seamless interior enhances comfort.     Polyester Text Synthetic Plastic