NIKE Men's Flex Experience Run 8 Sneaker 100% Leather and Synthetic Imported Rubber sole Shaft measures approximately low-top from arch Flex grooves in the outsole promote natural flexibility. Knit fabric conforms to your foot for a snug feel. Injected unit sole (IU) midsole provides a resilient ride and enough durability to double as an outsole. This allows for a reduction in rubber and overall weight. Hexagonal flex grooves are hot-knife cut to offer 6 different flex points for natural motion. Textured outsole provides additional traction and durability