MIZUNO ENERZY NXT: The next generation of MIZUNO ENERZY midsole material. Designed to maximize energy return and cushioning for optimum performance.Foam Wave: A Wave of comfort made of 2 layers of foam. Top layer is U4icX and bottom layer Mizuno EnerzyFoam Wave: A Wave of comfort made of 2 layers of foam. Top layer is U4icX and bottom layer Mizuno Enerzy