Nike Womens Dual Fusion Running Shoes Rubber Synthetic sole Breathable Mesh Upper - For breathability and a comfortable fit. Dual Density Phylon Foam - With soft foam in the center and firm foam at the perimeter for plush, supportive cushioning. Flex Grooves - At the midsole and outsole for enhanced flexibility and natural range of motion. Inner Sleeve - For a soft, comfortable fit. Waffle Lugs - Located at the outsole for better traction.