Made from CarbonX®, Chicago Protective Apparel undergarments provide protection from heat and flame, making them ideal for steel workers, welders and firefighters. The undergarments are made of a single layer of 7.7-oz. interlock knit. The CarbonX® fabric has a TPP rating of 14.7 and an ATPV of 12.3 cal/cm2.Chicago Protective Apparel, Skokie, IL.