|Duofold Mens Originals Mid Weight Ankle Length Thermal Bottom KMO3 fiber content is 100% Cotton inside / 65% Cotton, 25% Merino wool, 10% Nylon outside. Duofold Mens Originals Mid Weight Ankle Length Thermal Bottom Duofold Originals created the base layer category with the first bi-ply thermals. Each style is constructed to offer unbelievably soft cotton against the skin, paired with the natural warmth of wool for superior thermal insulation. Duofold Originals . Duofold Mens KMO3 comes with 1 Thermal Bottoms per Pack.