Lightweight and breathable, the women's Wild Rye Nona T-shirt is a do-it-all base layer to keep you moving in comfort from the skin track to the chairlift to relaxing back at camp.

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Beat the heat on summer adventures in the Odlo Performance Light Crew shirt. Organic body mapping and integrated ventilation zones provide ideal breathability when you're working up a sweat.

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Made from lightweight pin-dot mesh, this men's Saxx Quest long-sleeve crew base layer top is a versatile option for whatever your day has in store. Test it out on a quick hike or a misty morning run.

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Delivering moisture management and breathable warmth, the women's Arc'teryx Rho Lightweight Crew Neck long-sleeve base layer top keeps you comfortable with a trim fit for hustling in the mountains.

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Designed for lower output activities in cool temperatures, the women's Arc'teryx Rho Lightweight Hoodie base layer top is moisture-wicking, quick-drying, breathable and seriously soft.

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Comfort starts with your base layer. Made for wicking and warmth on low-output days, the women's Arc'teryx Rho Lightweight zip-neck base layer top feels supersoft, moves with you and layers easily.

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Skiing, backpacking or climbing, the Arc'teryx Rho Wool Long-Sleeve Crew women's base layer top is extremely versatile. It's fitted for easy layering, while stretch and articulation free up movement.

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Knit with a Nordic-inspired floral design, the women's Kari Traa Rose half-zip base layer top is made from insulating merino wool for next-to-skin comfort, natural odor-resistance and breathability.

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Made from lightweight fleece that's brushed on both sides, the kids' Odlo Royale half-zip mid layer has a high collar with half-length zipper so they can either seal warmth in or vent it as needed.

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Some wear it as a smoothing base for daily wear. Some wear it as a light and warm base layer under their gear. Either way, the women's REI Co-op Silk camisole makes a great foundation.

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Lightweight and supple, the REI Silk crew shirt provides great warmth for its weight and offers luxurious comfort.

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Lightweight and supple, the REI Co-op Silk long-sleeve crew shirt provides great warmth for its weight and offers luxurious comfort.

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Some wear it as a light and warm base layer under their gear. Some wear it as a smoothing base for daily wear. Either way, the women's REI Co-op Silk V-neck shirt is a great foundation.

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With low-profile seams to minimize bulk and maximize comfort, the women's Summit Pro 120 Crew base layer top is an adventure-ready, lightweight base layer made for cold-weather exploration.

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