Simpson CarbonX Racing Underwear is made from double jersey interlock knit comprised of a patented blend of high-performance fibers with inherent moisture wicking properties, and comfort. CarbonX based clothing offers the best protection against the potential extreme conditions that can occur during a race. It is inherently flame resistent, will not burn, melt or ignite when subjected to direct flame. CarbonX material has been known to last up to 20 times longer than the leading fire resistant fabrics. NOT SOLD AS A SET OF TOPS/BOTTOMS.