Game for any adventure, any time of year, the men's Smartwool Classic All-Season Merino quarter-zip base layer top is made from a lightweight jersey and built for comfort—even under your pack.

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Made from premium merino wool, the Smartwool Classic Thermal Merino Crew base layer top helps regulate your temperature with improved performance functionality while hiking or skiing in cold weather.

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

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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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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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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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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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As solid and dependable as its namesake rock formation in Colorado, the men's Artilect Flatiron 185 crew is durable yet comfortable and made for effortless, reliable performance in harsh conditions.

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Offering up personalized comfort, the men's Artilect Flatiron 185 Quarter-Zip base layer top gives you warm, fast-drying wool and a zipper that lets you vent or add heat to your core.

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Harnessing the warming power of Heatwave™ technology, the men's Seirus Heatwave Lite Reversible Long-Sleeve base layer top reflects heat back to your body, and is now available in a lighter design.

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Harnessing the warming power of Heatwave™ technology, the men's Seirus Heatwave Reversible Long-Sleeve Crew base layer top reflects heat back to your body to fend off winter's chill.

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Pack less and do more with the men's Mons Royale Icon Raglan top. You'll go from bike laps to alpine climbs and everything in between without having to change shirts.

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With mesh ventilation for cooling, minimal seams to help reduce chafing and a fit that moves with your body, the men's Smartwool Intraknit Active base layer top is ready to go the distance with you.

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With merino comfort, ventilation and articulated flex zones, the Smartwool Intraknit Thermal Max Quarter-Zip base layer top will be what you grab first for high-intensity, cold-weather adventures.

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