COLDPRUF Men's Authentic Thermal Crew-Neck Shirt two layer garment has been specifically engineered with the COLDPRUF® Insulation System to trap air between the layers of fabric offering the desired warmth and comfort in very cold to extremely cold weather conditions during low to medium activity.Flat seamsTaglessTrue sizing for accurate fitRib knit cuffsExtended tailMachine wash Product Features: Fabric:Inside: 100% Combed Ring Spun Cotton COLDPRUF Men's Authentic Thermal Crew-Neck Shirt