The 1000 Mile Ultimate Tactel Trainer Liner has a unique double layer construction to offer maximum comfort with no blisters The high wicking inner Tactel reg layer stays with your foot while the soft cotton-mix outer layer moves with your footwear in order to reduce friction and thus prevent blisters and reduce wear of the sock The unique combination of fibres maintains a comfortable temperature for the foot Arch braces on both layers help prevent unwanted movement even on severe slopes