CarbonX heat resistant socks offer the best level of fire and heat protection in fire resistant clothing in the most extreme conditions. Based on patented blends of oxidized fibers, CarbonX is the only fabric able to withstand the direct flame of a blow torch without melting, igniting, or burning—even when exposed to the flame for up to 20 times longer than the leading competition. CarbonX FR socks also retain this level of persistence and protection against molten metal and arc flash, leaving it as the only choice for professionals working in conditions where safety matters most. These 22" heavy knit crew socks are made of heavy knit protective material for the ultimate in heat and flame resistance.