Alpinestars TECH ZX Series STELLA BRIEFS are constructed with LENZING™ FR, an innovative, sustainably produced viscose fiber that provides exceptional flame resistance and protection against heat transfer. This Formula 1-derived underwear is extremely lightweight and thin, and designed to be incredibly soft to the touch, offering greatly enhanced comfort when wearing beneath mandatory underwear layers. Certified to FIA 8856-2018 homologation standard for Personal Underwear.