The Nike Free 4.0 Black/Cool Grey/White of Men's Nike Running Shoe features a seamless mesh upper and deep flex grooves for ventilated comfort and flexibility over any distance.BREATHABILITY AND NATURAL MOTIONOne-piece, seamless mesh with synthetic overlays for breathability and lightweight supportPhylite midsole that's durable enough to double as an outsole for cushioning and durabilityDeep diamond-shaped flex grooves for flexibility and a natural feelOutsole rubber in high-wear areas for durabilityNike Free OriginsAfter 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. In 2002, they examined a group of men and women with pressure-measuring insoles taped to their feet, using high-speed cameras to capture images of each foot in motion. The team spent eight years studying the biomechanics of shoeless running. 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....The Nike Shoes more colors