Stay dry on the trail in the soft, breathable and naturally odor-resistant REI Co-op Merino Merino Hipster Underwear for women. They're made to keep you comfy throughout the day.

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For reliable comfort at your very first layer, here's a go-to choice. Cut to fit your curves, this Smartwool Merino Lace thong breathes, wicks moisture, regulates temperature and resists odor.

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Ideal for cold weather, the kids' REI Co-op merino midweight base layer bottoms are soft—not scratchy—naturally regulate temp and made with wool that's certified to the Responsible Wool Standard.

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Oh so soft and not itchy, the kids' REI Co-op merino midweight base layer top is an ideal first layer for cold weather. It naturally regulates temp and is certified to the Responsible Wool Standard.

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Your underwear should deliver lasting comfort. Whether you're spending the day at work or a couple hours at the gym, Smartwool Merino Plant-Based Dye boxer briefs help you stay confidently comfy.

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A wide, merino-lined elastic waistband and flatlock seams help make Smartwool Merino Print boxer briefs your new favorite for any activity—from urban exploration to new trail adventures.

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Built with the outdoor enthusiast in mind, the men's Smartwool Merino Sport long-sleeve quarter-zip top provides thermoregulation, odor resistance and durability for years of adventure.

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Avoid panty lines on the trail in the soft, breathable and naturally odor-resistant REI Co-op Merino Merino Thong Underwear for women. They're made to keep you comfy throughout the day.

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Keep the winter chill away with the women's Icebreaker MerinoFine base layer leggings, which feature a high waist for added coverage—and its merino wool is naturally stretchy and odor resistant.

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An ideal performance layer, the men's REI Co-op Midweight Base Layer Bottoms boast a smooth face and low-bulk seams for easy layering and a brushed back for added warmth and comfort.

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Stay dry, warm and stoked all day with the men's Burton Midweight Base Layer Crew top, which gives you moisture-wicking fabric and comfortable, chafe-free seams.

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Hard-charging winter days start out cold, but you always warm up. The men's REI Co-op Midweight Base Layer half-zip top offers the warmth of long sleeves and the easy venting of a front zipper.

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The women's REI Co-op Midweight Base Layer Half-Zip Top offers warmth in the cold with long sleeves and easy venting thanks to a front zipper.

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Stay dry, warm and stoked all day with the men's Burton Midweight Base Layer pants, which give you moisture-wicking fabric with a cottonlike feel and a plush waistband.

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