What Our Gearhead® Experts Are Saying:“This one piece is the ultimate base layer for skiing, snowboarding, or even hut trips. It’s all the benefits of Smartwool’s 100% Merino wool in a seamless head-to-toe package, with details like a zippered drop seat and flatlock seams that make it super functional.”Built for the coldest days and longest adventures, the Smartwool Classic Thermal Merino Base Layer One Piece provides full-body coverage in one streamlined design. Made from 100% Merino wool, it naturally regulates temperature, manages sweat, and resists odor, keeping you comfortable from first chair to last run. A slim fit and interlock knit construction enhance warmth and next-to-skin softness, while thoughtful details like a zippered drop seat, set-in sleeves, and flatlock seams ensure all-day comfort. Whether you’re layering up for deep winter skiing or cozying up in the cabin, this one piece makes cold-weather layering simple and smart.