Designed to flex and expand with your foot, Nike Free TR 8 Women's Training Shoe features a rounded toe box and aggressive siping for optimal flexibility while you workout. Durable 3-D printing on a stretchy mesh upper equals a winning combination of structure, flex and breathability. 3-D printing on mesh upper for flexibility and breathability. Flywire cables integrate with laces for midfoot lockdown. Full bootie construction creates a sock-like fit. Injected unit (IU) midsole provides lightweight cushioning. Flat heel creates a wider surface area for enhanced stability. Flex grooves allow the foot to move naturally.