FXR Racing Riding Sock. One pair per pack. Lightweight acrylic / nylon sock with reinforced toe and heel. Silicone security strips on inner and outer elastic. Extra-long length to be worn with knee braces. Lightweight polyester / Spandex knit upper leg wicks moisture. Polyester / Spandex mesh back panel for ventilation. Ribbed arch and ankle support. Sizing: S/M: 27" height, fits Men's 5 - 8; Women's 6 - 9. L/XL: 28" height, fits Men's 9 - 13; Women's 10 - 13.