FLEXIBLE COMFORT. The Nike Flex Experience RN 8 Men's Running Shoe delivers snug, dynamic comfort on your run - and more. Mesh around the heel and flex grooves in the outsole promote a natural step that adapts to your movements. The flex grooves in the outsole promote natural flexibility. The knitted fabric adapts to your foot for a snug feel. The rounded heel promotes natural mobility. The seamless cover at the shoelaces and toe tips gives extra durability. The inserted unit (IU) in the midsole offers a resistant step and enough durability to also function as an outsole. This makes it possible to reduce the amount of rubber and the total weight. The hexagonal flex grooves are hot knife cut to offer 6 different flex points for natural mobility. The textured outsole offers extra grip and durability. Read: QD-39 Offset: 6mm (14mm forefoot, 20mm heel)