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.