A unique 2-in-1 base layer half-zip to with a with a warm-breathable 100% merino wool exterior and a 100% LIFA® wicking interior.LIFA® MERINO.2-layer construction.100% Merino wool exterior.Flat lock seams for ideal comfort and durability.Non-itch fabric.ZQ wool.Fabric composition:Shell:57% Merino Wool, 43% Polypropylene. Compare prices from: Helly Hansen in Men's Underwear