The new GEL-Kayano 21 is updated with nothing but the best in ASICS technical innovation, featuring the next generation of FluidRide and an Ortholite X-40 sockliner for the lightest and most luxuriously stable ride yet. Mild to moderate overpronators will enjoy a more comfortably secure upper, uniquely designed with a new heel construction that complements the premium FluidFit upper and Heel Clutching System.