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  • Made of a durable yet soft polyester / spandex blend that wicks sweat and dries fast
  • Tall neck extends coverage; zipper with chin guard lets you adjust ventilation
  • Flatseam construction, raglan sleeves and side gussets are comfortable as you move
  • Extended back hem stays tucked in when you lean forward
  • UPF 50 sun protection
  • Fitted

Made in USA.

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

REI membership


Best Use Multisport
Shirt Style Zip-front
Fabric Polyester
Sun-Protective Fabric Yes
UPF Rating 50
Moisture Wicking Yes
Quick Drying Yes
Underwear Weight Midweight
Sleeve Length Long Sleeve
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 Perfect light weight pullover I travel allot on airplanes and needed a light weight pullover, this is perfect. Doesn't wrinkle and fits nicely. Wish it had a small pocket. I'll use this winter as a base layer for skiing.
Date published: 2016-09-13
Rated 5 out of 5 by from Great Product Very comfortable, being just snug enough to look fitting but loose and stretchy enough to keep you from feeling constrained. The perfect weight and thickness for what I was looking for.
Date published: 2016-10-18
Rated 4 out of 5 by from Pretty good garment This is called a mid-weight shirt. What that means is that you cannot read a book through it like you can with many flimsy under layer tops. It didn't shrink when I washed it. (Yes some of the REI poly fabrics shrink and I don't know why). The fit is reasonable although true-to-size fit seems to be a thing of the past. So all in all it's pretty good
Date published: 2017-01-11
Rated 5 out of 5 by from Warm on a cold windy day I bought this item in preparation for a hike on the Oregon portion of the PCT and decided to try it on a local hike on the Oregon coast on a cold and windy day. This item kept me warm and was a pretty solid windbreaker also. Doesn't over heat you either. I can't recommend this item enough.
Date published: 2017-04-07
Rated 5 out of 5 by from Used for sking in Utah last month. Toasty. Well made mid weight base layer. Excellent construction. I would recommend highly.
Date published: 2017-01-11
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Regarding the REI Co-op Midweight Base Layer Half-Zip Top , how is the fit. Is true to size or cut smaller or larger? Depending I would need a large or an exlarge 

Asked by: Gary
​The fit is true to size and semi form-fitting.
Answered by: REIservice
Date published: 2017-05-11
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