1000 Mile Ultimate Heavyweight Walking Socks Navy 100% Tactel® inner stays with the foot, wicking away moisture, whilst the soft wool-mix outer layer moves with the shoe.  The lack of friction between the layers helps to prevent blisters and reduces wear.  This Socks is designed to be thicker than the 1000 Mile Lightweight Walking Socks to provide added volume, insulation and warmth.  Mid-calf length, ideal for 3 and 4 season walking in all boots.