Reinforced cushioned heel and toe for comfort and durability Broad elastic arch support in both the arch and ankle firmly keep the sock in place Heel tab aids in preventing the sock slipping into your running shoe Balega's Left/Right construction method ensures the perfect fit Sculptured mesh panels aid in ventilation Trademark Balega hand-linked seamless toe Unique triple Y heel creates a heel pocket which is ergonomically formed to the actual shape of your heel. In essence this creates a more formed and deeper heel pocket for ultimate fit and comfort.