Advanced ZX underwear series socks developed using an innovative flame resistant technology developed by Alpinestars. -- Complies withFIA8856-2000 homologation standard. -- Special material formulation offers more breathability than standard Nomex. -- Lightweight, seamlessconstruction designed to reduce pressure points. -- Fabric is extremely soft to the touch and flexible for enhanced comfort. -- Lenzing FR material is a special natural viscose ..