The NOVABLAST® 4 running shoe features a new midsole and outsole geometry that helps produce an energized ride. A tongue wing construction in the upper helps improve the fit while reducing tongue movement. It's complemented with an engineered woven upper that offers more stretch, ventilation, and durability. FF BLAST™ PLUS ECO cushioning is made with 20% recycled bio-based content. This material helps create softer landings and a more energized toe-off during your training. Engineered woven upper Offers advanced stretch, ventilation, and durability Tongue wing construction Added stretch helps improve the fit while reducingtonguemovement Gusseted tongue wing fit system Improves the midfoot fit and reduces tongue sliding FF BLAST™ PLUS ECO cushioning Made with approximately 20% bio-based content and helps provide cloud-like comfort Trampoline-inspired outsole design Helps provide a more responsive bounce back AHAR® outsole Improves durability