The lightest and most breathable nomex underwear available, Sparco's RW-10 line is optimized for the ultimate in fit and comfort. The super soft and stretchy fire resistant fabric makes for the ultimate balaclava with no seam down the center of the head sock for unsurpassed comfort under a helmet. Treated with Sparco's exclusive X-Cool treatment that draws head away from the skin to cool the driver on even the hottest days.