CarbonX can provide critical extra protection when every second counts. Unlike many of the most widely used fire-resistant fabrics on the market today, CarbonX won't char, shrink, or burn when exposed to heat and direct flame. Instead, CarbonX fibers will carbonize and expand, dramatically reducing the oxygen content within the fabric. This gives it performance far superior to other fire retardant fabrics. And its soft knit construction is very comfortable and efficient in wicking moisture away from your skin. Socks made one size for all.