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  • Durable polyester/spandex blend wicks moisture and dries quickly
  • Mineral-based LAVA™ finish keeps fabric odor-free
  • Flatseam construction and low-profile waistband and crotch gusset keep you comfortable as you move
  • UPF 50 sun protection
  • Fly opening
  • Fitted

Made in USA.

View all REI Co-op Men's Long Underwear Bottoms

REI membership


Best Use Multisport
Fabric 89% polyester / 11% spandex
Sun-Protective Fabric Yes
UPF Rating 50
Moisture Wicking Yes
Quick Drying Yes
Gender Men's

Size chart

Sizing notes

SHORT: Some pants are available in short sizes, which generally means an inseam that is 2.5 inches shorter than regular sizes. TALL: Some pants, shirts, jackets and parkas are available in tall sizes, which generally means an inseam that is 3 inches longer and a rise that is 1 inch longer, a shirt or jacket body that is 2 inches longer, a parka body that is 2.5 inches longer and sleeves that are 2.5 inches longer than regular sizes.

Rated 5 out of 5 by from What underwear? I'm an athletic guy and these fit snug in all the right places. The fabric wicks moisture like it's the only thing it's ever wanted to do in life. I wore these while boarding with the bros and my legs were toasty like the inside of a s'more. The fabric is smooth like Lionel Richie's Easy Like Sunday Morning. But don't get the wrong idea, the fabric still likes to party and is probably made from the same stuff Wolverine's claws are made of. They're strong. That's what I'm trying to say. Just buy them. You won't be disappointed. Unless you prefer to overpay for some other under-performing garment.
Date published: 2017-01-06
Rated 2 out of 5 by from Not great This layer is thin, warm, and stretchy. I tried country skiing in it and had a major problem. Every knee extension would pull the waist down. Stopped every 100 yards to pull my pants up. Finally got the process systemized...pull pants up first, then pull underwear just above the knee upwards for some slack. The more you sweat, the more pronounced the effect. I have a 35" waist, and 32" length, sort of a medium tall physique. My old Duofold underwear is saggy, baggy, thick and ugly but always functioned well.
Date published: 2017-01-08
Rated 4 out of 5 by from Christmas present for my dad Bought this to give to my dad for Christmas. Not sure if he needs a small or medium as his waist is about 31. The small looks fairly small, but the medium looks too big. I ordered both sizes as I'm not sure which one he'll wear since he is kind of in between. The fabric seems nice. I do have the REI brand heavyweight base layer shirt for myself, and I really like it
Date published: 2016-09-19
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How do I order a/o find in online catalog where an item is available in "short" or "long" sleeve and pant lengths?

Asked by: BruceB
​Short and tall sized items can be quickly filtered for using the size search facets in the left margin of any category page. Check them out here:
Answered by: REIservice
Date published: 2016-12-09

Would someone normally wear underwear under these

Asked by: Andrew69
Some do and some don't wear underwear under long underwear bottoms.
Answered by: REIservice
Date published: 2016-11-28

What arevthe lengths on the Regular men's med and Tall men's medium?

Asked by: Tango1
The regular medium inseam is 32 inches. The tall medium inseam is 35 inches.
Answered by: REIservice
Date published: 2016-12-08

Are these NTS 250?

Asked by: idahohiking
No, NTS – next to skin is a Smartwool designation. They are both Midweight, so are very close to the same weight.
Answered by: REIservice
Date published: 2016-12-07
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