Pioneered by SOREL after extensive field testing, the ThermoPlus Replacement Liner features four-layer construction for unbelievable cold-weather protection. The wicking polyester inner layer pulls moisture away from the foot, and thermal polypropylene transfers moisture to the moisture reservoir. The breathable Radiantax thermal reflective membrane keeps body heat in and cold out. The outer viscose moisture reservoir locks moisture away from the foot and promotes fast evaporation. Reinforced seams and heels provide exceptional durability, while the snow cuff adds extra warmth where you need it most. The stretch front shaft ensures a comfortable fit and further seals out cold air. Imported.