Duofold Varitherm Men's Wool Zip Dri-release wool: 84% Polyester / 11% Merino Wool / 5% Spandex base-layer-underwear closure Patented fabric combines quick-dry polyester with insulating Merino wool. This unique single-layer blend dries four times faster than wool alone. Plus, it provides warmth without weight and feels extra-soft next to skin. Knit-in spandex stretches 360 degrees for smooth fit and maximum movement. FreshGuard fabric system naturally resists garment odors. Thumb holes (in cuffs) and drop-tail hem add extra thermal protection. Tag free for no-scratch comfort, with non-chafe flat-locked seams 84% polyester/11% Merino wool/5% spandex. Dri-release and FreshGuard are registered trademarks of Optimer Performance fibers.