G-FORCE flame-retardant underwear is essential for providing the last line of defense in a fire. The extra layer of flame retardant material is an item that no driver should ever have to use, but, if you need it, you will be glad you have it. The soft knit is hypoallergenic and more comfortable on the skin than the old standby. The double stitching provides added durability. SFI 3.3 certified.