Sidi kaos air shoes sidi kaos air shoes offering a high quality fit and technically advanced designfeaturing sidis millennium 4 carbon composite sole made using a mixture of carbon and nylon offering more rigidity than the standard nylon solethe soft instep 3 closure system is adjustable from both sides to evenly distribute pressure over the arch areathe two other closure mechanisms allows the shoes to be adapted to your individual foot shapethe reinforced heel will keep the foot in place wh