Carry one in your duffel when you're traveling among ancient watchtowers, slip one on for a spin around Adam's Gulch or use one as a pillow on the train to Monterosso. Worn alone in hot conditions, our lightest-weight Merino baselayer exchanges heat and moisture between your skin and the air to keep you cooler and more comfortable. It also layers easily as part of a system for colder weather. Merino wool is naturally breathable, regulates body temperature and stretches. It's also wonderfully soft and naturally resists odor. Ours is responsibly sourced from the grasslands of Patagonia. We slow wash it for softness and shrink resistance, without the use of chlorine, then blend it with 35% Capilene polyester (100% recycled) for durability and for dry times and moisture transfer superior to that of 100% merino. Features include a self-fabric collar with internal neck tape for chafe-free comfort, full underarm gussets for unhindered shoulder mobility, elastic thumb loops for secure hand coverage, low-bulk merrow seams to minimize chafing, offset shoulder and side seams to lie smoothly beneath pack straps, and a drop tail for additional coverage. Machine wash cold; machine dry at low temperatures. Fabric is bluesign approved.