TUNED FLEXIBILITY, NATURAL SUPPORT. The Nike Free RN Distance 2 Men's Running Shoe lets your foot move naturally with an ultra-flexible outsole that provides just enough support and cushioning to help you cover any distance.Natural Flexibility The Nike Flex outsole expands and contracts to allow your foot to move naturally from heel-strike to toe-off.Breathable Comfort Breathable fabric in the forefoot and internal sleeve helps keep your feet cool and comfortable.Supportive Fit Flywire technology—strong, lightweight cables that provide support—bring a secure, locked-in fit through your midfoot.More Benefits Dynamic Fit technology provides a secure, adaptive fitSoft, responsive Lunarlon cushioning helps absorb impactLoosely woven fabric in the forefoot for natural stretchWeight: 249 grams approx. (men's size 9)Offset: 4mmNike Free Origins After learning that Stanford athletes had been training barefoot on the university's golf course, three of Nike's most innovative and creative employees set out to develop a shoe that felt natural and weightless, similar to bare feet. The team spent eight years studying the biomechanics of runners' feet in motion. The results yielded a profound understanding of the foot's natural landing angle, pressure and toe position, allowing Nike designers to build an unconventional and flexible running shoe from the inside out.