|Duofold Womens Varitherm Brushed Back Rib Ankle Length Thermal Bottom BBP4 fiber content is 100% Polyester. Duofold Womens Varitherm Brushed Back Rib Ankle Length Thermal Bottom Duofold Varitherm performance base layer helps protect you from the element during high activity sports. Features: Soft, single layer thermal for warmth in cold weather. Brushed inside for added warmth and comfort. Flatlock seams to avoid irrita. Duofold Womens BBP4 comes with 1 Thermal Bottoms per Pack.