Authentic 2-Layer Originals Midweight Thermals are constructed with the same insulating Duofold 2-layer technology in a slightly lighter weight. The Authentic Originals fabrics feature a 25% Merino Wool blend in the outer layer along with an inner layer of 100% Pure Cotton. Content: Outer Layer - 65% Cotton, 25% Merino Wool, 10% Nylon----Inner Layer - 100% Cotton |