Nunn Bush Men's Squall Slip-on 100% Synthetic NuBuck Rubber sole Comfort gel heel pod for shock absorption Thermo plastic shank is airport friendly Full-length EVA footbed provides support and maximizes cushioning Perforated footbed for increased breathability Opanka construction where the upper, sock lining and outsole are hand-sewn together in a single process for the ultimate in flexibility and comfort Subtle ventilation panels enhance the comfort of this classic casual shoe.