Double layer construction coupled with the most technically advanced fibers, delivers the blister protection that you need, guaranteed * The outer layer is constructed of performance fibers specific to each activity the interaction between layers absorbs friction which prevents blisters * Two layers trap air for effective insulation from heat and cold * Inner layer is smooth, undyed, hydrophobic dri-wright wicks moisture away for cool, dry feet * Patented 3rd attachment keeps socks properly aligned