The 1000 mile ultimate tactel liner sock has the unique double layer construction to offer maximum comfort with no blisters but in an incredibly versatile liner sock that can be used either on its own in the warmer months or teamed up with a thicker traditional walking sock in the colder months this 1000 mile liner sock comes with their blister free guarantee the double layer construction eliminates friction between shoe and sock thus reducing friction between sock and foot the skin should there