Reaching beyond is no obstacle when you're floating in the Wave Sky 8. Comfort is key thanks to the innovative MIZUNO ENERZY NXT providing an even softer and more responsive experience than before. The new upper provides a comfortable secure fit and is even lighter than its predecessor for the ultimate floating feeling. Foam Wave: A Wave of comfort made of 2 layers of foam.  Top layer is U4icX and bottom layer Mizuno Enerzy Foam Wave: A Wave of comfort made of 2 layers of foam.  Top layer is U4icX and bottom layer Mizuno Enerzy MIZUNO ENERZY NXT: The next generation of MIZUNO ENERZY midsole material. Designed to maximize energy return and cushioning for optimum performance. X10 Outsole: Durable carbon rubber that allows for longer wear. Eco Friendly Materials: Recycled materials Gusseted Tongue: Stretchy tongue lining that hugs the foot securely and comfortably without any stress. MIZUNO ENERZY (FOAM): Offering versatility in its application, while still maintaining softness and resilience.  It will help enhance performance capabilities.