Impact Racing 78900613 Underwear - Top, Long Sleeve, Yth X-Lg, Gry. Gain valuable additional seconds of heat and thermal protection with the use of Impact’s fire retardant base layer manufactured from our line of lightweight ImpactMAX soft-knit aramid fabric and available in a natural white or charcoal gray. Our soft yet durable fire retardant underwear is form fitting and hand-crafted with a flat interlock stitch to minimize pressure points while providing cooling comfort through the use of our exclusive moisture-wicking aramid fabric. Available in long sleeve tops and full-length pants, Impact’s works perfectly under any driving or crew suit and provides an additional layer of valuable protection. Adult Sizes: XS/S/M/L/XL/2X/3X