Running Xtra - Anti Blister System. The "Original" plus Xtra Cushioning for Added Protection Against Blistering. Dri-Wright Polyester/Microsafe Inner Layer. Hidden Terry Looped Dri-Wright Polyester Outer Layer. For the Runner who wants more Cushion. Content: Inner Layer: Dri-Wright Polyester 55%, MicroSafe 15%, Nylon 30%/Outer Layer: Dri-Wright Polyester 78%, Nylon 19%, Lycra 3% |