Built to stretch with you and still retain its shape, the women's Artilect Boulder 125 Crew base layer top combines merino wool and nylon for an incredibly soft and durable fabric.

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Dump heat—or add more—with the thermoregulating ventilation of the men's Artilect Boulder 125 Quarter-Zip base layer top. It stretches with you and keeps its shape after all your adventuring.

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Combining merino wool and nylon for an incredibly soft and durable fabric, the women's Artilect Boulder 125 Quarter-Zip base layer top stretches with you and still retains its shape.

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Worn as a technical training base layer for outdoor activities, the Threads 4 Thought Brennan base layer long-sleeve quarter-zip top is soft and stretchy and has all the tech qualities you seek.

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High performance in cooler months begins with a great base. Working from the inside out, this Craft CORE Dry Active Comfort base layer top is soft and functional—essential to your winter gear.

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High performance in cooler months begins with a great base. Working from the inside out, the women's Craft CORE Dry Active Comfort base layer top is soft, functional and essential to your winter gear.

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Lightweight, soft and warm, the men's Patagonia Capilene Air base layer hoodie insulates even when wet, dries quickly and resists odors for days of use whether you're on the trail or the slopes.

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What wicks moisture, resists odor and dries in a flash? The women's Patagonia Capilene Air hoodie made from an airy blend of merino wool and recycled polyester.

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Lightweight, soft and warm, the men's Patagonia Capilene Air crew base layer top dries quickly, insulates even when wet and resists odors for days of use whether you're on the slopes or the trails.

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With a wool-Capilene® blend that offers the greatest range of comfort of any Patagonia base layers, the women's Capilene Air Crew top insulates even when wet, dries quickly and resists odor.

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Warm, breathable and quick-drying for daily wear, the men's Patagonia Capilene Midweight Crew base layer top incorporates HeiQ® Fresh durable odor control to cut the funk and keep the fabric fresher.

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Stay cozy on chilly forest treks and snowy alpine adventures. An ideal choice for cool-weather quests, the men's Patagonia Capilene midweight zip-neck base layer top keeps you comfy on the move.

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Hitting the sweet spot in weight, breathability and wicking performance, the women's Patagonia Capilene Midweight Zip-Neck base layer top keeps you dry and warm in cold-weather excursions.

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When a foot-wide ledge becomes your bed for the night, this women's compressible zip-neck top helps turn up the heat.

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