Made of heavyweight merino wool, the men's Smartwool Classic Thermal Merino quarter-zip base layer top helps regulates your temperature during high-intensity skiing, hiking or running in cold weather.

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Whatever high-intensity activity you get into, the women's Smartwool Classic Thermal Merino quarter-zip top delivers exceptional performance and improved functionality to keep you warm, dry and comfy.

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Stay comfortable, dry and warm in the plus-size Smartwool Classic Thermal Merino quarter-zip top while enjoying your favorite activities year-round. An improved, active-minded fit is designed to move.

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Engineered for the most demanding athletes in the toughest conditions, the men's Artilect Darkhorse 185 Zoned base layer top get you in the zone with lightweight and durable merino wool.

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Whether you layer it or wear it on its own, the Obermeyer Discover base layer crew top offers a flatseam construction for comfort, a soft brushed interior and fun one-of-a-kind colors and prints.

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Whether you're carving through the snow or walking through town, the women's Obermeyer is an ultra-light base layer designed to move with your body, excelling in any conditions, on any mountain.

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Thanks to its supersoft merino wool fabrication, the Kari Traa Elenore women's base layer T-shirt pulls double duty to keep you warm or cool to suit the conditions of your hike.

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Thanks to its merino wool fabrication and flatlock construction, the Kari Traa Elenore women's long-sleeve base layer top feels cozy and comfy next to the skin, no matter the activity.

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You can stop looking for that ideal base layer. The tasc Performance Elevation Merino men's T-shirt offers superior temperature regulation and moisture management without the bulk.

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Look no further for that perfect base layer. The women's tasc Performance Elevation Merino T-shirt offers superior temperature regulation and moisture management without the bulk.

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Let it snow! The women's Kari Traa Else Half-Zip base layer top blends soft merino wool and modern fabric mapping to keep you warm and comfortable on or off the slopes.

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With the same silhouette as the original but in a lighter-weight blend, the women's Wild Rye Evie Lite Raglan base layer top will keep you warm (but not too warm) from spring skiing to summer camping.

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Made with 100% merino wool, the Wild Rye Evie raglan base layer top offers a looser, contemporary fit and longer silhouette that work to keep you comfortable on the skin track or chairlift.

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Purpose-built for advanced insulation and unrestricted mobility, the men's NRS Expedition Weight base layer shirt layers seamlessly under drysuits, helping paddlers hit the water in cold conditions.

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