ColdPruf Men's Authentic Dual Layer Long Sleeve Wool Plus Crew Neck Base Top 100% Other Fibers Imported Inside: 100% cotton, outside: 50% cotton, 40% Merino wool, 10% nylon, imported Flat seams, tag less and extended tail for comfort Ring spun yarns provides exceptional softness True sizing for accurate fit Thermachoice system: extreme cold weather/low to medium activity