The Nike Free OG 2014 Cool Grey/Black/Neutral Grey/Neutral Grey of Men's Nike Shoe offers barefoot-like flexibility and excellent breathability for everyday comfort. NATURAL FLEX AND COMFORTBenefits Lightweight textile and synthetic leather upper for reduced bulk and durable comfort Perforations for excellent breathability Nike Free midsole with deep sipes for a barefoot-like feel Outsole rubber pods at heel for durability in high-wear areasNike 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