|Duofold Mens Varitherm Brushed Back Rib Ankle Length Thermal Bottom BBP2 fiber content is 100% Polyester. Duofold Mens 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 Mens BBP2 comes with 1 Thermal Bottoms per Pack.